No fellowship with sin
It is indeed, in the highest degree, pure, chaste, clean, holy. Otherwise it could not be the immediate offspring, and much less the express resemblance of God, who is essential holiness. It is pure from all sin, clean and unspotted from any touch of evil. It is a chaste virgin, incapable of any defilement, of any mixture with that which is unclean or unholy. It has no fellowship with sin of any kind. For what communion has light with darkness (2 Corinthians 6:14)? As sin is in its very nature enmity to God, so his law is enmity to sin.
1771 text
3. It is indeed, in the highest degree, pure, chaste, clean, holy. Otherwise it could not be the immediate offspring, and much less the express resemblance of God, who is essential holiness. It is pure from all sin, clean and unspotted from any touch of evil. It is a chaste virgin, incapable of any defilement, of any mixture with that which is unclean or unholy. It has no fellowship with sin of any kind. For what communion hath light with darkness? As sin is in its very nature enmity to God, so his law is enmity to sin.