Apostate prophet is undecisive; who holds the correct belief in Jesus?

In answer to the video "Top 5 Misconceptions About Islam - Debunked (Merciful Servant)"

1Jn4"do not believe every spirit, but test the spirits to see whether they are from God..Every spirit that acknowledges that Jesus Christ has come in the flesh is from God. This is how we recognize the spirit of truth and the spirit of falsehood".

This means that anyone recognizing Jesus as a human being sent by God can be said to have "the spirit of truth" in him such as Muhammad, and by extension the Muslims, as opposed to the spirit of falsehood dwelling in the world that rejects Jesus as God's human envoy. This paints trinitarians as spirits of the antichrist since they do not recognize that "Jesus Christ has come in the flesh" but that "God has come in the flesh".

Jesus' mission and message wasnt complicated at all.

Jesus did not proclaim anything dissimilar to what his contemporaries expected from an Israelite prophet. Jesus was the final prophet in a series of prophets sent to the Bani Israel exclusively Matt10:5-6,15:24-26,21,Quran3:49, to warn them of their constant betrayal of their covenant with God, including their hiding and distortion of the true expression of the Torah, just like Moses foresaw Deut31:25-29 and Jeremiah confirmed Jer2:8,7:21,8:8,23:9-36.

Being the last one in the line of Israelite prophets, Jesus had to prophecy the coming of the final prophet who would be sent to all of mankind and he did so through his prophecies of the paraclete, as echoed in the Quran 61:6. It is this distinction between the prophet Muhammad and the other prophets that makes his prediction a necessity, by his predecessors from among the Israelites, Moses and Jesus included 6:20,7:157,61:6. Muhammad is the only prophet whom the Quran says was announced by previous prophets. 

As to Jesus, one can clearly see from his few reported NT sayings that he did not come to establish a new religion. That is why the earliest Christian creed was simple and concise as compared to the one grossly inflated centuries later at Nicea then Constantinople so as to integrate new theological notions. Although speculations were rife about Jesus' nature and relationship with God the Father, prior to the 4th century, the authorities of the church did not view the persons of the trinity as equal in divinity. The Father was understood as the supreme God and the Son came second in worship, subordinate in knowledge and power, followed by the Holy Ghost as third in rank.

Jesus, per the Quran, came to verify the truth remaining in the Torah 

3:50,5:46,61:6"verifying what is between my hands MIN/OF the Torah". 

Just as the prophet Muhammad was tasked in doing with the Quran, Jesus wasnt going around listing every single error and absurdity of the scriptures and traditions that preceded him. His words and deeds testified to the truth and falsehood in them. Most of those words and deeds have been forgotten, misinterpreted or purposefully put aside by the gospels writer's own admission. These writers reported what was transmitted to them with their heavy pagan Hellenistic perspective, if not outright fabricated events that do not stand the test of internal and external scrutiny. Their sole purpose was to advance the notion of Jesus being "the messiah, the son of God" as candidly admitted in Jn20:31. 

The Quran gives several examples of how his words and deeds testified to some of the corruptions of the HB. For example when Jesus, with God's leave, creates life from inanimate material and resurrects the dead, these were meant to demonstrate to an audience highly skeptical of the concept of resurrection how life can be gathered from dust and how a lifeless body can be risen back. During the volatile transmission process of the HB, such concepts, like the concept of an afterlife were almost entirely blotted out from their books. These actions from Jesus acted as a criterion of what is true and false in the HB, confirming the very few passages vaguely attesting to resurrection. The near scriptural absence of those concepts was an obvious manipulation. Because of their sins for which they were successively destroyed and humiliated during their tumultuous history, the Israelites became averse at the notion of an afterlife in which one is resurrected and held accountable for his worldly deeds. And so they progressively denied the concept, leading to the polemics within their sects during Jesus' time. The Pharisees forcefully argued in favor of the concept, using scattered biblical references including 1Kings17:17-24,2Kings4:17-37,13:20-1,1Sam2:6,Isa2:17,26:19,66:14,Ezek37:1-28,Ps71:20,Prov6:22,Prov31(see Rashi),Dan12:1-2 while their main opponents, the Sadducees strongly denied that basic monotheistic tenet.

Jesus' purpose was in addition to allow some of the things that were forbidden to them through the traditions of men (NT Matt15,23). He was the most qualified to do so, through his inspired knowledge

 3:48"And Allah will teach him the Book and Wisdom, the Law and the Gospel". 

That is why he is depicted in the NT as turning the people's attention away from their oral man-made traditions, and focus instead on the true divine source which he claimed to fulfill to the letter Matt5:17-20. In that passage, the "Law and the Prophets" was a regular expression Jews of Jesus' day used in reference to the entire HB Matt7:12,22:40,Acts24:14,28:23,Rom3:21. The fulfillment of the Torah refers to the revival of its spirit, which the Jews had neglected by focusing more on baseless rituals, and issuing ever new conjectured complications to those rituals, attributing their origins to the revealed Oral Torah/Talmud. These additions had distorted Moses' religion beyond recognition Mk7:7. 

Humans, because of their very nature as volitional creatures are bound to differ in almost every aspect of life, as stated elsewhere in the Quran. This isnt necessarily an evil, however the only sphere in which they should not contend but rather unite are the original and clear tenets of the religion. The innovations of the Jews in that area inevitably caused dissension among them and Jesus came to unite them by clarifying their misunderstandings and/or deliberate distortions

43:63"And when Isa came with clear arguments he said: I have come to you indeed with wisdom, and that I may make clear to you part of what you differ in; so be careful of (your duty to) Allah and obey me".

Jesus wasnt an all-knowing being charged with resolving every conflict, his function wasnt to unify them in every aspect of life, but only in the relevant religious matters hence the statement in the verse "part of what you differ in". The Quran here again, as it does in countless places, demonstrates its surgical precision in its meaningful choice of every word. To further corroborate, when God the all-knowing best of judges swift in reckoning will resurrect and gather the people, He shall judge between them in all that which they differed 

39:46"Say: O Allah, Originator of the heavens and the earth, Knower of the unseen and the seen! Thou (only) judgest between Thy servants as to that wherein they differ".

Perfect judgement and final resolution of conflicts is only possible in the hereafter, at God's court of justice.

What is very revealing and that most Christians are oblivious of, is that after the councils of Hippo and Cartage in the end of the 4th century where 27 books were finally canonized as NT scriptures, one would expect the Church to want its adherents to get to know the official books of the Church. Especially when there were many non-canonical books in circulation, competing sects and heresies. And yet this is absolutely not what happened. Not only were the people discouraged from reading the Bible on their own, but translations into native languages were prohibited (Council of Toulouse 1229, Tarragona 1234, Constance 1415), forcing translation efforts to go underground. Some were burned for doing so (Tyndale 1536). With the proliferation of unreliable versions, the church authorities had no choice but to begin an effort of official translations, especially done in the monasteries. Two main reasons motivated this concealment by the Church. First to maintain their own aura of elitism. Among the reasons Martin Luther was persecuted in the 1500s was because of his translation, giving the lowly folk access to the "lofty" Bible.

Compare this to the early efforts of the Quran compilers just 10 years following the prophet Muhammad's death, to spread copies of the book in scripts that would unlock the primitive consonantal structure of the text.

The second and most important reason for the Church's reluctance to make its canon accessible to the commoner, was to prevent Christians from finding out about Jesus' purely Jewish environment, teachings, legacy, as well as the Jewishness of his followers, prior to Paul's appearance on the scene. Despite all of Paul's missionary activities, early Jewish converts to Christianity still worshiped in synagogues until the late 4th century (Homilies against Jews by Chrysostom). The dominant Pauline Church wanted and needed to break with Jesus and his early followers' Jewish heritage. Something that would have been impossible to do as early on in the history of Christianity where the traditions transmitted by the original cluster of Jewish sects claiming descendency from Jesus and his followers, were still known. Instead the church presented limited editions to the people, they could not show the full version because the Gospel writers didnt and couldnt erase Judaism from Jesus' ministry. They couldnt do it, because it would have made Jesus contextually irrelevant, as if appearing in a vacuum.

Through a concise statement, the Quran explains the mutual relationship between the Torah and the Gospel; they complete one another by centering the attention on the wisdom and spirit of every aspect of God's Laws so that they do not end up as something lifeless and burdensome for the people

3:48-50"And He will teach him the Book and the wisdom and the Tawrat and the Injeel..And a verifier of that which is before me of the Taurat and that I may allow you part of that which has been forbidden to you, and I have come to you with a sign from your Lord therefore be careful of (your duty to) Allah and obey me".

By the beginning of the 1st century Judaism was a sterile, lifeless organism, waiting to be infused with a spirituality that only Jesus could provide.

Jesus repeatedly condemned those traditions in the NT, denounced the Jews and their leaders as "hypocrites" and told the people to beware of these "teachers of law" for their soulless traditions, and "children of the Devil" because of their claim of inherited righteousness through their affiliation to Abraham Jn8:37-44.

Not in one single instance within the whole NT is it reported that Jesus said that the law of Moses needs to be abandoned, contrary to Paul who besides stating it was a curse Gal3:13 given not by God but by angels Gal3:19-25,Heb2:2 declared it obsolete Rom3:20,7:4,10:4,Heb8:13,Gal2:21,3:23-25,4:21-31,5:1,Eph2:15 even describing his former Jewish beliefs as worthless, rejecting his former Jewishness by warning of Jewish dogs saying in the original Greek

Phil3:2-8"I consider them excrement".

He told people he was seeking to convert that they were now under the vague 'law of Christ'. Jesus himself never alludes to such law, hence it being unknown to any of those who met and followed him and respected all Jewish laws to the letter as per his actual instructions. That law of christ, tailored so as to appeal to Paul's mainly pagan audience, has removed the old burden from mankind 1Corin9:21,Gal6:2. He sometimes paid lip service to the Law if the situation or audience required a show of obedience to the law Acts21:20-26 but immediately denounced the likes of James and Peter for telling the Gentiles to follow the law Gal2, evidently because it attracted less converts.