Mark (13:22) says that false Christs and false prophets shall rise, and shall shew signs and wonders, to seduce, if it were possible, even the elect. Matthew (24:24) repeats this message, and also warns of false prophets a further two times. Luke does not warn against false prophets.
Acts of the Apostles identifies Bar-jesus as a false prophet and paints him a a bad light. Paul wrote frequently about those who taught a "different Christ" and in ironic terms of the "super apostles" who opposed him.
It appears from this that early Christianity was in a state of tension, while various different theologies contended for supremacy. Each author warned against the teachings of others with a different Christian message, but we can not be entirely sure to which group various New Testament books might have belonged.