Behold! Allah took the covenant of the prophets, saying: “I give you a Book and Wisdom; then comes to you a messenger, confirming what is with you; do ye believe in him and render him help.” Allah said: “Do ye agree, and take this my Covenant as binding on you?” They said: “We agree.” He said: “Then bear witness, and I am with you among the witnesses.”
If any turn back after this, they are perverted transgressors.
Yahiya Emerick writes:
God took a covenant with the (ancient) prophets (and their followers), saying, “I’ve given you the scripture and the (source of) wisdom. If another messenger ever comes to you (after your time), who confirms the truth of what you now possess, then (your descendants) must believe in him and help him.” (Then God) said, “Do you agree to this pledge?” To which they answered, “Yes, we agree.”  Then (God) said, “So witness (your promise), even as I’m witnessing it along with you.  Whoever breaks (this pledge) after this will be openly rebellious.”
This prophetic covenant is a general summary of what Judaism and Christianity both teach. Both the Old and New Testament make allowance for future prophets and hold that believers in those times must follow them. Muslims who have examined the Bible have identified several passages in which they believe Muhammad (or at the least, Angel Gabriel) was foretold. Deuteronomy 18:15-22 would be the prophecy for the Jews foretelling Muhammad, while John 16:7-14 may be the prophecy for the Christians. In that last passage, a man who extols Jesus as a true sign of God is clearly being mentioned. Verse 13, especially, mirrors exactly the Qur’anic notion that Muhammad merely repeats the revelation that he hears from God. (Also see John 14:30) How can any of these things apply to a holy ghost, who, as supposedly part of God himself, would not be so subservient as to merely parrot phrases put in his mouth?
Emerick, Yahiya. The Meaning of the Holy Qur’an in Today’s English (p. 111, 829). Unknown. Kindle Edition.