What Does the Bible Say About Confronting Friends With Bad Theology?

"The prudent see danger and take refuge, but the simple keep going and pay the penalty."

"When Cephas came to Antioch, I opposed him to his face, because he stood condemned. For before certain men came from James, he used to eat with the Gentiles. But when they arrived, he began to draw back and separate himself from the Gentiles because he was afraid of those who belonged to the circumcision group. The other Jews joined him in his hypocrisy, so that by their hypocrisy even Barnabas was led astray. When I saw that they were not acting in line with the truth of the gospel, I said to Cephas in front of them all, 'You are a Jew, yet you live like a Gentile and not like a Jew. How is it, then, that you force Gentiles to follow Jewish customs?'"

"Preach the word; be prepared in season and out of season; correct, rebuke and encourage—with great patience and careful instruction."

"Instead, speaking the truth in love, we will grow to become in every respect the mature body of him who is the head, that is, Christ."

"Be merciful to those who doubt; save others by snatching them from the fire; to others show mercy, mixed with fear—hating even the clothing stained by corrupted flesh."