We do have a verse in the Quran which mentions this issue. The verse says: “And when Jesus son of Mary said, ‘O Children of Israel! Indeed I am the apostle of Allah to you, to confirm what is before me of the Torah, and to give the good news of an apostle who will come after me, whose name is Ahmad.’
We do have a verse in the Quran which mentions this issue. The verse says: “And when Jesus son of Mary said, ‘O Children of Israel! Indeed I am the apostle of Allah to you, to confirm what is before me of the Torah, and to give the good news of an apostle who will come after me, whose name is Ahmad.’ Yet when he brought them manifest proofs, they said, ‘This is plain magic.’” Islamic researchers have said that the glad tidings which this verse has narrated from the Prophet Jesus (‘a) can be found in the Gospel of John in the 14th, 15th, and 16th chapters. This gospel has mentioned the coming of an individual after Jesus (‘a) by the name of Fārqliṭ. There is much contextual evidence which shows that this name is a reference to the Prophet of Islam (saww). In order to further understand this issue, we are going to narrate some verses from this book:
“If you love me, then keep to my law and I will ask the father to send the other Faraqleet, and he will remain with you for eternity. He is the spirit of truth which the world cannot accept. This is because they cannot see him and they cannot understand him, yet he knows you all. He will be amongst you all and within you.” “I have said these words to you whilst I was still amongst you. But the father is going to send Faraqleet in my name and he will teach you all things and he will remind you of the things that I have taught you.” “I have given you word of this before his coming in order that you will have faith when he comes.” “The Faraqleet whom I am going to send to you from father is the spirit of truth who will come from father and he will bear witness in regards to me.” “I speak the truth in that it is good for you that I go, for if I was not to go, then that Faraqleet will not come to you. But if I go, then I will send him to you and when he comes, he will command the world in regards to sin, truthfulness, and justice. This is because they will not have faith in me in truth and I will go to my father and you will not see me any longer…. I have many things to tell you but you cannot bear them right now, but when he comes, he will guide you towards all of the truth for he does not speak from himself, but he will say only what he hears. And he will give you word of the future and he will praise me… What is from my father is from me and…. He will take what is from me and give you news of it.”
At this juncture, we have some evidence that shows that Faraqleet is a prophet who will come after Jesus (‘a) and he is not a reference to the Holy Spirit:
1- The first point that we should consider is that according to Christian history, it was commonly known in the pre Islamic era amongst the scholars and commentators of the Bible that Faraqleet was in reference to a promised prophet. Some individuals even misused this well known concept and proclaimed themselves to be the promised Faraqleet. For example, look at the case of Muntasir, an ascetic who lived in the second century A.D. In the year 187 A.D., he announced that he was a prophet and said: I am Faraqleetes whom Jesus gave news of. A group of individuals likewise followed him.
2- From the historical reports, it is likewise clear that the Christian scholars and leaders who lived during the time of the Prophet (saww) were all waiting in expectation of the prophet promised in the Bible. One example this can be found when the Prophet (saww) sent a letter inviting various kings and leaders to Islam. When his ambassador took one of these letters to the king of Abyssinia, the king first read the letter and then he turned to the ambassador and said the following to him: I give witness that he is the same prophet that the People of the Book have been waiting for. Just as Moses (‘a) gave news of the coming of Jesus (‘a), Jesus (‘a) also gave news of the last prophet and he has mentioned his signs as well.
When the letter of the Prophet (saww) reached the Caesar, he first studied it and asked in regards to the particularities of the Prophet (saww). He wrote the following in his response: I have read your letter and I have become aware of your invitation. I have known that a prophet was to come but I always assumed he would be from Syria… We can clearly understand from these historical sources that these individuals were all awaiting a prophet and so this belief had some firm foundations in the Bible.
3- The characteristics which Prophet Jesus (‘a) has described for Faraqleet, as well as the conditions related to his coming, all show us without any doubt that this Faraqleet is none other than the promised prophet. These indicators simultaneously show that these verses are not in reference to the Holy Spirit. The reasons behind this are as follows: A- Prophet Jesus (‘a) began his words as follows: ‘If you love me, then keep to my law, and I will ask my father to send you another Faraqleet.’ Firstly, the Prophet Jesus (‘a) reminds the people of his love and this shows that perhaps some of his followers may not want to follow anyone else who will come at a later period. Through the use of emotion, he is trying to ease that acceptance. If the intent behind the term Faraqleet was the Holy Spirit (just as modern day Christians believe it is), then there was no need for such prerequisite words.
Furthermore, the Holy Spirit would have had such an effect on the hearts and spirits of men that there would have been no room for any doubt or rejection on behalf of the Christians. But if the intent behind this term was the promised prophet, then there clearly would have been a great need for such prerequisite words. This is because the promised prophet would use the methodology of natural propagation in order to affect change in the people and it is due to this reason that some would follow him and some would reject him.
Prophet Jesus (‘a) did not stop at this advice either; he continues in the 29th verse of the 14th chapter and says: “I have told you (this) before the coming so that you will have faith when it comes”. This is while faith in the Holy Spirit does not require such advice and admonishment; clearly this advice is for something else. The second point is that he has mentioned ‘another Faraqleet will come’ and this shows that the intent is another prophet and not the Holy Spirit, since the wording shows it to be someone similar to Jesus (‘a). Such a term would not have been used for the Holy Spirit, since there is only one Holy Spirit and no more.
B- The passage then says: “Whatever I have said to you, he will remind you of it” (14:26). Another line says: “The spirit of truth, which will come from the father, will testify in regards to me.”(15:26)
It has been mentioned that the Holy Spirit came to the disciples fifty days after the crucifixion of Jesus (‘a); did these elite few forget the instructions of Jesus (‘a) in such a short period of time and require another visit from the Holy Spirit in order to remind them? What need did the disciples of Jesus (‘a) have for the Holy Spirit to testify for them? So in reality, if the intent of these lines is the coming of another prophet, then it makes complete sense, for after the passing of some time, the Christians forget much of the teachings of Jesus (‘a) both due to the distortions of their scholars, as well as the effects of the passing centuries. When the Prophet Muhammad (saww) came, he reminded the Christians of the original teachings and he testified to the prophethood and message of Jesus (‘a). The Prophet (saww) said in regards to Jesus (‘a) that: ‘He was a prophet like me’. He also dispelled various wrong ideas in regards to Mary, the mother of Jesus (‘a) and also rejected the divinity which the Christians had invented for him.
C- “If I do not go, then Faraqleet will not come to you.” (15:7). Apparently, the coming of Faraqleet was conditional on the leaving of Jesus (‘a). If the meaning of this term was the Holy Spirit, then such a condition would not apply since according to Christian belief, the Holy Spirit came to the disciples when the Prophet Jesus (‘a) was going to send them towards their own missions. According to this logic, the coming of the Holy Spirit was never conditional on where Jesus (‘a) was. Yet if the meaning of this line was in the coming of a new prophet then it makes perfect sense, since such a prophet would abrogate certain aspects of the previous religion.
D- The gospel mentions three things that will happen with the coming of Faraqleet: “He will command  the world in regards to sin, truthfulness, and justice…” (16:8). We know that according to Christian belief, the Holy Spirit visited the disciples fifty days after the crucifixion of Jesus (‘a) and he did not command them in regards to ‘sin, truthfulness, and justice’. In addition, the verse seems to imply that he is going to visit the rejecters and not the disciples, who were the closest of believers. Yet again, if we were to say that this line is referring to the promised Prophet of Islam (saww), all of this would clearly apply to him.
E- “Faraqleet will testify in regards to me.” (15:26) “He will tell you of the future and he will praise me” (13:16). This issue of testifying further shows that the intent of the term Faraqleet is not the Holy Spirit for the disciples had no need of his attestment; the issue of praise was something that was fulfilled by the Prophet of Islam (saww) and it is something clearly seen in the Quran and the Islamic traditions. Furthermore, the Prophet (saww) completed the religion which Jesus (‘a) had brought and there is no praise higher than such an action. When we pay attention to these pieces of evidence, we are guided to the reality of this matter and the conclusion that Islamic researchers have arrived at. It is interesting to note that this issue doesn’t just stop here, there are even more pieces of evidence that can be researched if the need arises.
In conclusion, we would like to quote a statement from the Great Encyclopedia of France  on this issue which mentions the following: “Muhammad is the founder of Islam, the messenger of God, and the seal of the prophets. The term Muhammad means ‘a great deal of praise’ and it comes from the root word of ‘praise’… Based upon a strange coincidence, a synonym of Muhammad is the term Ahmad which was most probably used by the Christians of Arabia as the name of Faraqleet. The term Ahmad means one who is greatly praised and glorious. It is the translation of the term Paricletes which has sometimes mistakenly been pronounced as Paracletes. Due to this reason, Muslim writers have repeatedly mentioned that this word is news of the coming of the Prophet of Islam. The Holy Quran has also explicitly mentioned this issue in the Chapter of Ṣaff.”
 Surah Ṣaff, verse 61.  The Gospel of John, 14, 15, and 17. This version of the gospel was p r i n ted in the year 1837 in London and the rest of what we are going to narrate will be used from this same text.  Chapter 14, p. 25 and 26.  Chapter 14, verse 29.  Chapter 15, verse 26.  Chapter 16, p. 7-15.  Anīs al-A’lām, vol. 2, p. 179; narrated from the history of Līm Miur, which was published in the year 1848.  Ṭabaqāt Kubrā, vol. 1, p. 259; Sīrah Ḥalabī, vol. 3, p. 279.  Tārīkh Kāmil, vol. 2, p. 44.  Matthew, 10:29; Luke, 10:17.  In many of the older versions of the Bible, the term censure has been used instead of command. The term command is much more clear and suitable in the context of the verse.  The Great Encyclopedia of France, vol. 23, p. 4174.  Muhammad Khātame Payāmbarān, vol. 1, p. 504.  The book Anīs al-‘Alām, composed by Fakhr al-Islām has been used in the organization of this section.  Collected from the following books: An Answer to Various Religious Questions by Ayatollah Makarem Shirazi and Ja’far Subḥānī, Madrasah’ Imam ‘Ali Ibn Abī Ṭālib (‘a), second p r i n t, p. 161.