In contemporary period Sikhs have been staunch opponents of the idea that Baba Guru Nanak was a Muslim. They seek to disregard all evidence and instead parade around with "evidence" from the Guru Granth.
In my research I found a recurring pattern that Jamaat Sources said that Sikhs believed that this Chola came from heaven. Nowadays Sikhs try to claim the Chola was a gift from some Mislims. Considering how this idea kept repeating itself I decided to look into it and I found it was true.
I have decided to quote from two books. One is the The Founder of the Ahmadiyya Movement by Maulvi Muhammad Ali and First Volume of The Great Reformer by Dr. Basharat Ahmad.
Regarding the Chola Maulana Muhammad Ali states:
Guru Nanak’s Chola
In 1895, he turned his attention to Sikhism, another offshoot of Hinduism, which had gained considerable strength in the Punjab. His enquiries into the religious scriptures of the Sikhs led him to the conclusion that the founder of Sikhism had not only come under the influence of Muslim Sufis but that he was in fact a Muslim, though the movement started by him took a different turn owing to political reasons. To set a seal on this conclusion, he undertook a journey to Dera Nanak, a village in the Gurdaspur District, and one of the sacred places of Sikhism. A chola (cloak), which is a relic of Guru Nanak himself and which is in the custody of his descendants, is preserved there. It is a long cloak with short sleeves and is made of brown cloth. A tradition in the Sakhi of Bhai Bala, more commonly known as Angad’s Sakhi, states that the chola was sent down to Nanak from heaven and that upon it were written the words of nature in Arabic, Turkish, Persian, Hindi and Sanskrit. Upon Nanak’s death, the chola passed to his first successor, Angad, and thus to successive Gurus, till the time of the fifth Guru, Arjan Das. In his time, the chola was obtained by Tola Ram, in recognition of some great service done. After some time, it fell into the hands of Kabli Mal, a descendant of Nanak, and, since then, it has remained in the hands of his descendants at Dera Nanak. On account of the high repute and sanctity in which the chola was held by the followers of Nanak, the practice became common at an early date of offering coverings to protect it from wear and tear. The mystery which surrounded the chola became deeper by the increased number of coverings which hid it altogether from the eye of the worshipper. Only a part of the sleeve was shown, but, by constant handling, the letters on that part became quite obscure
As the founder of the Ahmadiyya movement had already come to the conclusion that Guru Nanak was in fact a true Muslim, he also thought of solving the mystery enshrouding the chola. Accordingly, on 30th September 1895, he started, with some of his friends, for Dera Nanak. By special arrangements made with the guardian of the chola, the numerous coverings, mostly of silk or fine cloth, were taken off one by one, and the actual writing on the chola was revealed. This was nothing but verses of the Holy Quran, and they were at once copied. This wonderful disclosure of the writing on the chola showed clearly that Nanak was a Muslim at heart. The result of the investigation was published in a book, called Sat Bachan; and though the orthodox Sikhs were greatly aroused when it appeared, yet the truth of its statements concerning the chola has never been questioned. (FOUNDER OF THE AHMADIYYA MOVEMENT pg. 47-48)
And:
Chola Sahib (The cloak of Baba Nanak) In addition to the above evidence, the Janam Sakhi of Guru Angad was emphatic in stating that Baba Nanak frequently wore a cloak received from heaven and bearing some heavenly inscriptions. After his death, the cloak was preserved as a relic in Dera Nanak, and Sikh religious leaders of consequence considered it a matter of great blessing to view the cloak and make offerings at the temple where it was kept. It was also stated that whenever Sikhs were beset by difficulties, they supplicated with their head on the cloak and God removed their difficulties. These descriptions aroused Hazrat Mirza’s curiosity, and he decided to investigate the reality behind these assertions. (The Great Reformer pg. 550-551)
Regarding the Pothi Sahib:
Pothi Sahib (The Revered Book)
Hazrat Mirza did investigative research on Pothi Sahib, another revered relic of Baba Nanak, in April 1908 and the findings were published in his book Chashma Marifat (Fountain of Knowledge) in May of 1908. However, since the evidence regarding the Islamic faith of Baba Nanak, of which the cloak is the centerpiece, has been presented here, it is conducive in the interest of continuity to mention also the findings about Pothi Sahib. The narration that follows is based upon information provided by members of the research team sent by Hazrat Mirza to Guruharsahay in the Ferozepur district to find out the truth about Pothi Sahib. The members of the team who provided information for this report included Mufti Muhammad Sadiq, Maulvi Muhammad Ali and others.
Hazrat Mirza had received reports that there was a relic of Baba Nanak called Pothi Sahib in the village of Guruharsahay. The relic was in the hands of the descendants of Guru Ram Das, the fourth guru of the Sikhs, after whom the famous Golden Temple of Amritsar was also named. The descendants of Guru Ram Das first resided in the village Muhammadipur near Chunian in Lahore district, but then an elder of the family by the name of Guru Jiwan Mal moved away from Muhammadipur and founded a village—their present place of residency—which he named after his son Guruharsahay. At the time of the research instituted by Hazrat Mirza, Guru Bashan Singh was the head of the family and the custodian of the relic that had been passed down to him by his forefathers who had come to view the book was the Maharaja of Faridkot. Normally, the book was kept wrapped in many scarves and was exhibited with the wrappings to the devotees who would place their forehead on the wraps and depart. Very few people had been privileged to actually see and examine the book. The reason was that an uncovered viewing of the book required an offering of one hundred and one rupees to the custodian guru, who then had to bathe one hundred and one times before he was considered fit to touch this pure and holy book. Therefore, on rare occasions when a very affluent Sikh devotee with a strong desire to see the book came and made the offering, the actual book was taken out for viewing after the requisite baths had been taken by the custodian guru
On getting this information, Hazrat Mirza’s enlightened soul at once perceived that Pothi Sahib would furnish some additional evidence about the Islamic creed of Baba Nanak. Accordingly, he dispatched a delegation of his disciples to Guruharsahay for this investigation. Coincidently, Syed Amir Ali Shah, a disciple of Hazrat Mirza, was a sub-inspector of police in Jalalabad, Ferozepur district, and the village of Guruharsahay fell under his jurisdiction. On reaching Jalalabad, the delegation went straight to him and sought his help in the matter. He replied: “You have come at a very opportune time. There has been a theft in the house of this Guru in Guruharsahay and I am going there to investigate it. You can come with me.” The delegation then accompanied him to Guruharsahay.
Guru Bashan Singh received them hospitably. A member of the delegation said: “Guru Ji! The greatest gesture of hospitality for us would be to view the Pothi Sahib.” Guru Bashan Singh replied, undoubtedly with an eye to winning the favor of the sub-inspector: “You are in luck! A devotee has only today left an offering of one hundred and one rupees with me. Tomorrow I will bathe one hundred and one times and will open the Pothi Sahib for him. You can view the Pothi Sahib at the same time that he does, and that way you will not have to make a separate offering.”
The next day, which was April 4, 1908, Guru Bashan Singh started taking the ritual one hundred and one baths, and it was many hours before he was done because the taking of so many baths is no small matter. Finally he was ready to touch the pure book. When the Pothi Sahib was brought, it was wrapped in layers of expensive scarves just like the cloak of Baba Nanak. One by one the wraps came off and finally the book was revealed from underneath its many coverings. When the book was opened, the delegation was astonished to see that the Pothi Sahib was a copy of the Holy Quran. Starting from the Chapter Fatihah and ending with wannas, the last word of the Quran, the Pothi Sahib was the Quran in its entirety. It was a hand-written, pocket-sized version of the Quran, with the text on each page bordered by golden lines. Guru Bashan Singh said: “The language in which it is written is unknown to us. It is some heavenly language that Baba Nanak alone could understand.” His statement was correct because the current guru was illiterate in Arabic. Had he known the Pothi Sahib to be the Quran, he would never have allowed an investigating team of Muslims to see it. The delegation returned home after the viewing, their faith refreshed by what they had seen. They thanked Allah and sent salutations on His Messenger all the way on their journey home. When they narrated the details of their trip and their findings to Hazrat Mirza, his happiness knew no bounds. He said: “This latest evidence has put the final seal of authenticity on our finding that Baba Nanak was a Muslim.” Accordingly, he prominently announced these findings in his book, Chashma Marifat. Whether the Sikhs accept it or not, there is no doubt that Hazrat Mirza has provided convincing evidence of Baba Nanak’s Islamic creed. (The Great Reformer pg 556 - 558)
Sikhs often get riled up when we, Ahmadi Muslims, say that Baba Guru Nanak was a Muslim and start being hostile. This is nothing new and Hadrat Ahmad(as) encountered this. Not only did he respond to them but he challenged them. The following massage from Mujaddid-e-Azam (The Great Reformer by Dr. Basharat Ahmad) should elcuiate on what transpired
Rajinder Singh challenged
Rajinder Singh challenged In the midst of these battles with Christians and Hindus that kept him busy day and night, a Sikh by the name of Sardar Rajinder Singh jumped into the fray. The Sardar felt slighted at Hazrat Mirza’s claim in his book Sat Bachan that Guru Baba Nanak was a Muslim. The Sardar retaliated by writing a book Khabat Qadiani (Crazy Man of Qadian) in which he levied impertinent and vile charges against the Holy Prophet and stated that a holy person like Guru Nanak could never accept him as the Messenger of God. Hazrat Mirza was greatly pained by the impertinent and vile allegations, and immediately responded with a public rejoinder published on April 18, 1897, entitled “Listen Carefully Sardar Rajinder Singh Sahib!” In this announcement, addressed to Sardar Rajinder Singh directly but indirectly to all Sikhs, he adduced powerful arguments against the beliefs of the Sikhs. In one place, he addressed the Sardar as follows:
Although every nook and cranny is home to a different faith, and the disciples of each narrate the miraculous tales and stories of their prophets and spiritual leaders, and relate the miracles mentioned in their scriptures and holy books, the question is where is the proof substantiating these stories? And which ones should we consider to be true and which ones false? And if these stories were true, then how did this calamity come about that all that remains in the hands of these people are stories? The light of those who are true is eternal. In all fairness, can the truth of past events be established just by talk? Whether somebody likes it or not, I must say with complete honesty that the only true religion out of all these religions is the one that is blessed by the hand of God, and the only acceptable religion is the one whose light is resplendent in all ages; not one whose claim rests on the past. So hearken! I bear witness that Islam is that shining religion that has the support of God at all times. How pious and honorable is that Prophet who is a constant source of light and how holy is he whose love causes the Holy Spirit to reside in us. Because of this, our prayers are accepted, and marvels occur at our hands. This is the only way to witness the reality of the living God; all others merely deify the dead.
Where are the worshippers of dead deities? Can these deities speak? Where are the worshippers of the created? Can they take the field against us? Where are those people who said maliciously that our Prophet, may peace and blessings be upon him, never made any prophecy and never showed any signs? Listen! I tell you that they will be put to shame and will soon be looking for places to hide. That time is not far, in fact it is here, when the truth of the light of Islam will be like a slap on their faces and they will not know where to hide.
It should also be remembered that I have seen Baba Nanak in a vision twice and he professed that his light had been obtained from the same source. Frivolous and false talk is the act of carrion eaters. I say only that which I have seen. For this reason, I view Baba Nanak with great respect because I know that he drank from the same fountain from which we drink. And God knows that I speak from the knowledge that has been bestowed on me.
If you reject the notion that Baba Nanak was a Muslim and in addition you insist that our Prophet, peace and blessings of Allah be upon him, was, and I seek refuge in Allah from making this statement, an evil man, then I do not want to merely prove my point with the above arguments alone. Instead, I would like you to experience the final verdict of God by a way that I will describe shortly. I do not rely merely on the arguments adduced above because you will find them difficult to accept, not having had the benefit of hearing the opinions of those who are qualified to comment. You have heard only the criticism of ignorant Christian clerics and other similarly vulgar and uninformed persons. You accept it as the truth because of your innate rancor, and you then start maligning our Prophet, may the peace and blessings of Allah be upon him, without any independent inquiry and investigation. I know fully well that this haste to judgment, mixed with ignorance and prejudice, has thrown the world into a destructive turmoil, and a slanderous tradition has emboldened these people to try and spit on the sun. How great would be their regret if they had eyes, and how much would they weep at their folly if they had the true vision?
Further on, Hazrat Mirza proposes the method by which the contention with Rajinder Singh, and indirectly with the whole Sikh community, could be resolved:
This is the method by which I propose to produce a divine verdict against you: Your contention is that Baba Nanak sahib was not a Muslim while I say that in reality he was a Muslim…Secondly, you claim (and I seek God’s protection from saying it) that our Prophet, may the peace and blessing of Allah be upon him, was an evil and sinful person, and that Baba Nanak sahib was averse to him…The matter can be resolved in the following way. If you are convinced of your stand, then take an oath before a general assembly of men to the effect that ‘In reality, Baba Nanak was averse to the religion of Islam and thought ill of the Prophet of Islam and also, in reality, the Prophet of Islam, (and I seek God’s protection from saying it), was sinful and evil and not a true Prophet of God. If both of these things are against the facts then, O Almighty God, punish me with a terrible affliction within one year for this blasphemy.’ If you agree to take this oath, I will deposit five hundred rupees with anybody you trust. If you are truthful, not a hair on your head will be harmed and you will become the beneficiary of five hundred rupees while disgrace and infamy will be my lot. However, if you are inflicted by a calamity, then the entire Sikh community will be reformed. I know that Sikhs have a relationship with Islam that Hindus do not, and therefore, Sikh’s will be able to recognize a heavenly sign more easily. You are not cowardly like the Hindus but are a brave community, and, therefore, I hope that you will accept this method of judgment. First, you will have to publish in a newspaper that you are ready to take an oath of the form mentioned above. Then, after you have received our printed statement, you will have to come to Qadian and take the oath three times in a public gathering.
I hope that you will accept this proposal without any hairsplitting. Listening to these never-ending abuses has bruised our hearts. If we are false, then infamy and disgrace will be our lot and we will die an accursed death. If we are truthful, then our God will do justice. I implore you in the name of Permeshar1 to whom you consider Baba Nanak was close, and beseech you by the honor of Baba Nanak to accept this test. If you do not accept the challenge to take an oath as elucidated above and resort to ignoble excuses, then let the whole world witness that these few lines have proven your book to be false. 2
Those lacking full comprehension of these matters often ask why prophecies of calamity and death are made repeatedly? What kind of tidings do those who abuse the holy men of God deserve? This is what transpired in the days of the prophets and this is also what is written for the Promised Messiah: “The unbelievers will perish by his breath,” which means that his supplications will bring down calamities on them. So if these prophecies of calamity are a reason for infamy then this infamy has fallen to my lot by the word of God.
Hazrat Mirza appended a Persian verse at the end:
People malign my reputation, 3
If this displeases You, then change this situation.
Sarder Rajinder Singh chose not to engage Hazrat Mirza, and this refusal furnished the ultimate proof of his falsehood. The reader should consider Hazrat Mirza’s announcement and appreciate the strong and firm conviction that he had in the truth of Islam. Not for a moment did he have any misgivings about his stand. The Quran likens such persons to a tree “whose root is firm and whose branches are high” (14:24). Hazrat Mirza begged and pleaded and invoked the honor of Baba Nanak to induce Rajinder Singh to enter the contest, and even offered a reward of five hundred rupees. It was as if Hazrat Mirza saw the living God before him Who would cause the truth to prevail and destroy the evil if the opponent dared to take the oath. On the other hand, one does not see the same degree of faith exhibited by Rajinder Singh and others like him among the Arya Hindus and the Christian and Muslim clerics; these opponents were constantly procrastinating and evading a confrontation. Their faith was reminiscent of the Quranic analogy that compared such people to “an evil tree pulled up from the earth’s surface; it has no stability” (14:26), indicating that such people merely talked but lacked solid foundations. They did not have the moral courage to take the field against Hazrat Mirza and to state their stand on oath. The firm belief, faith and conviction as exhibited by Hazrat Mirza are the typical hallmarks of spiritually elevated individuals. Such strength and firmness is a source of astonishment for all.
1 Hindu name for chief god.
2 (Note in original document) I promise you that any loss you suffer at the hands of a human will not be considered a result of my supplication. I will be vindicated only if, without human intervention and merely as an act of God, you are inflicted within one year by an untreatable disease, a calamity or disaster that will ultimately prove fatal. If this does not happen, then I am a liar and you are entitled to receive five hundred rupees.
3 The literal translation is: “My passage through the alley of good reputation has been blocked.”
[THE GREAT REFORMER pg 648-652]
If Sikhs want us, Ahmadis to give up the belief that Baba Guru Nanak was a Muslim then they should know it is impossible as it is an essential belief of an Ahmadi in Ahmadiyyat.