1 Corinthians 15:33
Do not deceive yourselves: "Evil companionships corrupt good morals."
2 Timothy 2:17-18
and their teaching will spread like a running sore. Hymenaeus and Philetus are men of that stamp.
Hebrews 12:15
Be carefully on your guard lest there be any one who falls back from the grace of God; lest any root bearing bitter fruit spring up and cause trouble among you, and through it the whole brotherhood be defiled;
Revelation 18:4
Then I heard another voice from Heaven, which said, "Come out of her, My people, that you may not become partakers in her sins, nor receive a share of her plagues.