Acts 11:8

But I said, By no means, Lord: for nothing polluted or unclean hath ever entered into my mouth.

Romans 14:14

I know and have been taught by the Lord Jesus, that nothing is unclean of itself: only to him that thinketh any thing unclean, to him it is unclean.

Mark 7:2

and when they saw some of his disciples eating with impure (that is, unwashed) hands, they found fault:

1 Corinthians 7:14

For the unbelieving husband is sanctified in the wife, and the unbelieving wife is sanctified in the husband: else were your children unclean; but they are holy.

Treasury of Scripture Knowledge

Summary

But I said, Not so, Lord: for nothing common or unclean hath at any time entered into my mouth.

Bible References

Common

Mark 7:2
and when they saw some of his disciples eating with impure (that is, unwashed) hands, they found fault:
Romans 14:14
I know and have been taught by the Lord Jesus, that nothing is unclean of itself: only to him that thinketh any thing unclean, to him it is unclean.