Matthew 7:15
Take heed then of false prophets, who come to you in the garb of sheep, but inwardly they are ravening wolves.
2 Corinthians 11:13-15
For such are fake apostles, deceitful labourers, transforming themselves into apostles of Christ.
Galatians 1:8-9
But though even we, or an angel from heaven, preach unto you another gospel, different from that which we have preached to you, let him be an anathema.
1 John 4:1
BELOVED, believe not every pretender to inspiration, but bring these spirits to the trial whether they are of God; because many false prophets are gone forth into the world.
Romans 1:21
because though they knew [there was] a God, they glorified him not as God, nor gave him thanks, but became triflers in their disputations, and their stupid heart was darkened.