Matthew 7:15
"Beware of false prophets, who, indeed, come to you in sheep's clothing, but within are ravening wolves.
2 Corinthians 11:13-15
For such men are false apostles, deceitful workers, transforming themselves into apostles of Christ;
Galatians 1:8-9
But even if we or an angel out of Heaven should proclaim a Gospel to you other than that which we delivered to you, let him be accursed!
1 John 4:1
Beloved, believe not every spirit, but try the spirits, whether they are of God; because many false prophets have gone forth into the world.
Romans 1:21
because, having known God, they did not glorify Him as God, nor did they give thanks; but they became vain in their reasonings, and their senseless heart was darkened.