Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
2 Corinthians 6:14Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness?
1 Thessalonians 4:3For this is the will of God, even your sanctification, that ye should abstain from fornication: