"When he, the spirit of truth is come, he will guide you unto all truth; for he shall not speak of himself; but whatsoever he shall hear (from God), that shall he speak, and he will show you things to come. He shall glorify me" .
In Jesus' written portrait of the last messenger he is called the "Comforter", which represents the word parakletos in the Greek New Testament. More precisely, parakletos means an advocate, one who pleads the cause of another, one who counsels or advises another from deep concern for the other's welfare . Parakletos would designate one who would be considered the "Mercy for all creatures", Rahmatun lil 'Alamiun (Qur'an 21:107). He would be the counsellor who would "lead forth those who believe and do righteous deeds from the depths of darkness into light" (Qur'an 65:11), the true advocate who would be harisun 'alaykuym (Sura Al-Tawba); genuinely solicitous for the welfare of humanity, pleading their case with God and showing them the sure way of return to the favor of the divine Judge.
THE GREEK WORD "PARACLETE" (Ho Parakletos):
However, some scholars believe that what Jesus said in his own language of Aramaic represents more closely the Greek word periklytos, which means the Admirable or Glorified One. Periklytos corresponds to the word Muhammad in Arabic . There are several proven cases of similar word substitutions in the New Testament (Also, refer to added comments at Reference  at the bottom of this page).
There are also several instances of another possibility, the possibility that the Greek text originally had both words, parakletos and periklytos, and due to the similarity of spelling and close proximity to one another in the sentence, one got left out by the copyists. In such case the Greek text would have read: instead of the present reading: that is, "and He will give you another Counsellor, the Admirable One", instead of the present reading, "and He will give you another Counsellor". Such mistakes occured in copying because the ancient texts had all the letters written close together. The eye of the copyist could easily pass over a word similar in spelling or close in position .
When Jesus declares of his coming prophet-counsellor that he would "abide with you forever", he shows thatthere would be no need for additional prophets to succeed him. He would be the last one. He would lead mankind "unto all the truth" (Greek: "to the whole truth", "to every aspect of the truth"); there would be no necessity for anyone to come with additional truth. Indeed, there would be no more additional truth, in the general sense, to bring. So truthful and trustworthy would he be that he could be called Al-Amin, or as the Greek text of John 16:13 says, ,"the spirit of truth", one of whom it could be said: "He has brought them the Truth" (Qur'an 23:70).
The term "spirit" here does not mean that the coming prophet would be other than human. In New Testament Greek, this word has also been applied to an inspired person, "the possessor of a spiritual communication" or revelation. The one who become overwhelmed with a divine revelation is himself termed a "spirit" . The "spirit of truth" would be the person who would possess a spiritual communication, that is, a divine revelation, and whose life and conduct and character would be marked to an extreme degree by devotion to the truth. This is why the next sentence of the verse containing the expression says: "He will guide you unto all truth; for he shall not speak of himself, but whatsoever he shall hear (from God), that shall he speak" (John 16:13). This person would receive the revelation of truth from God and these words alone would constitute the message, not his own opinions or the writings of his companions. His message or revelation would be first and foremost and literally the Word of God. Note that this corresponds exactly to what God revealed to Moses about the prophet who would come from among the "brothers" of the Hebrews: "I ... will put My words in his mouth, and he shall speak unto them all that I shall command him" (Deuteronomy 18:18).
A more striking point is the similarity between the divine mission given to Moses, Jesus and the Spirit of Truth (Muhammad) as bearers of a single thread of Revelation from God. By comparing Deuteronomy 18:15, 17-19; John 12:49; 16:12-13; and Qur'an 73:15, one observes that despite the thousands of years involved and the disastrous human interference in the Bible, the words describing these three personalities are almost identical. Therefore, the (original) Torah, Gospel and the Qur'an have One Source and reveal the same Truth, which is Eternal.
It cannot be overlooked that Jesus gives a unique requirement that would help to identify the last prophet: "He shall glorify me". (John 16:14). If anyone had come claiming to be this prophet, but did not give due honor to Jesus as prophet and Messiah, he would the wrong one. As a nation, the Jews rejected Jesus. At the same time, this prophet to come would not be a follower of Jesus, that is, a Christian, because Jesus said that this prophet would reveal things of which Jesus himself was unaware. If Jesus had brought "all the truth", there would have been no need for him to single out someone else who would come with all the truth. Likewise, since this prophet would bring all the truth he would have to be the last one, the seal of the prophets. Therefore, we would have to look for someone who, like Abraham in whose line he would come, would be neither Jew nor Christian but would believe in God. Unlike the Jews as a whole, he would "glorify" Jesus by insisting that Jesus was a true messenger of God and by acknowledging that Jesus was the true Messiah. But the teaching of this prophet would come fromGod Himself. As a revelation from God, the message of this last prophet would confirm what God had revealed previously by means of the original Torah and the original Gospel, but his message would be no mere plagiarized copy, no "condensed edition" of either the Torah or the Gospel. God Almighty had said, "I ... will put My words in his mouth", and it is proper that these words would agree with previously revealed words of the One and Same God. "Whatsoever he shall hear (from God), that shall he speak".
The one reference at John 14:26 which seeks to identify the coming prophet as "the Holy Ghost" or Spirit is the only one like it in the entire Bible. It is obviously the addition of some editor of the Gospel of John who sought in his own way to explain who he thought the "spirit of truth" was. But this indefensible exegesis simply contradicts what Jesus is reported to have said elsewhere in John. According to other verses he indicated clearly that the prophet or "Paraclete" would not come until Jesus' own mission was finished. The holy spirit- the angel of revelation-was active already, both before and during the ministry of Jesus, delivering God's revelations to His prophets and assisting them. (see Psalms 51:11; Matthew 3:16; 4:1, etc.). This strange "Holy Ghost" interpretation gained currency only after Christians began to look upon God as a "Trinity", with the "Holy Ghost" being an aspect of it. Neither the word Trinity nor its concepts can be found anywhere in the Bible. The Paraclete would be a man, not a ghost, because the same word is applied to Jesus himself at 1 John 2:1
"We have a Paraclete (Advocate, Counsellor) with the Father, Jesus Christ, the righteous one". Jesus had been a "paraclete" to the Jews and his followers so considered him, but the Paraclete to come after Jesus (John 14:16) would be for all people, all places and all times.
The Greek text at John 14:16 which foretells the coming of "another Paraclete" is so specific that even the word "another" has significance. In English, "another" may mean "one more of the same kind" or "one more of a different kind". It is important to know which meaning Jesus had in mind, because if he meant "one more of a different kind" that would mean the Paraclete would perhaps be a spirit and the current Christian interpretation has some merit. But if he meant "one more of the same kind", then this is positive proof that the Paraclete would be just like Jesus was: a man, a human being, a prophet, not a spirit. Which did Jesus mean? The Greek text of the New Testament gives the verdict clearly because it uses the word allon, which is the masculine accusative form of allos: "ANOTHER OF THE SAME KIND". The Greek word for "another of a different kind" is heteros, but the New Testament does not use this word at John 14:16. Clearly, then, the Paraclete would be "ANOTHER OF THE SAME KIND" as Jesus, or as Moses said, "Like unto me": a MAN, not a spirit.
 John 14:16,17
 John 16:13, 14. It may be argued that Jesus was speaking for the benefit of his contemporaries, who died at least 500 years before Muhammad (pbuh). But many are the examples in the New Testament wherein Jesus, though speaking with his immediate followers, actually addresses his remrks to different generations in a future time. For example, see Matthew 16:27, 28. Jesus talks about Judgement Day but says, "Verily I say unto you. There be some standing here, which shall not taste of death, till they see the son of Man coming in his kingdom", and at Matthew 24:3, 34, while speaking about the Last Day, he declares, "Verily I say unto you. This generation shall not pass, till all these things be fulfilled". Obviously, those disciples with Jesus then did not live to see either Judgement day or the Second Coming of Jesus, neither of which has even yet occured. Jesus' words, though given to his contemporaries, had reference primarily to a time far distant in the future. When Jesus says "I say unto YOU", he means his followers in the general sense, i.e., "you my people". Jesus is identifying in John 14 and 16 the Last Prophet for the benefit of his followers who would be living when he appeared.
 Joseph H. Mayfield. Beacon Bible Commentary (Kansas City, 1965), Vol. VII, p. 168
 Hastings, op. cit. p.14. Added Comment: Note the striking similarity between the two words parakletos and periklytos in Greek:
the two words parakletos and periklytos in Greek:
The consonants are exactly the same, the difference is only in the vowels, increasing the possibility of substituting one word for the other or omission of the one through careless copying.
 For example, compare the many restorations of words and phrases made on the basis of ancient manuscripts, which were omitted from the standard New Testament text, as found in The Emphatic Diaglott of B. Wilson.
 Reverend Thomas S. Green, A Greek-English Lexicon to the New Testament, 26th Ed. (London, n. d.), p.149. As examples, see usual Christian interpretation of 1 Corinthians 2:10; 2 Thessalonians 2:2 or I John 4:1-3.