3 Bible Verses about Bad Relationships

Flee from fornication. Any other sin that a human being commits lies outside the body; but he who commits fornication sins against his own body.

Do not deceive yourselves: "Evil companionships corrupt good morals."

Do not come into close association with unbelievers, like oxen yoked with asses. For what is there in common between righteousness and lawlessness? Or what partnership has light with darkness?