1 Corinthians 15:33

Do not deceive yourselves. Evil companions ruin good morals.

Ephesians 5:11

and have no fellowship with the unfruitful works of the darkness, but rather expose them.

Titus 1:15

All things are pure to the pure; but to the contaminated and the faithless nothing is pure, nay, their very minds and consciences are tainted.

Treasury of Scripture Knowledge

Summary

Every bed, whereon he lieth that hath the issue, is unclean: and every thing, whereon he sitteth, shall be unclean.

Bible References

Be unclean

1 Corinthians 15:33
Do not deceive yourselves. Evil companions ruin good morals.
Ephesians 5:11
and have no fellowship with the unfruitful works of the darkness, but rather expose them.
Titus 1:15
All things are pure to the pure; but to the contaminated and the faithless nothing is pure, nay, their very minds and consciences are tainted.