Acts 11:8

But I said, 'By no means, Lord; because a common or an unclean thing never entered into my mouth!'

Romans 14:14

I know, and have been persuaded in the Lord Jesus, that nothing is unclean of itself: except that to him who accounts anything to be unclean, to him it is unclean.

Mark 7:2

and saw that some of His disciples ate bread with defiled, that is, unwashed hands.

1 Corinthians 7:14

For the unbelieving husband has been sanctified in the wife, and the unbelieving wife has been sanctified in the brother; else your children are unclean; but as it is 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 saw that some of His disciples ate bread with defiled, that is, unwashed hands.
Romans 14:14
I know, and have been persuaded in the Lord Jesus, that nothing is unclean of itself: except that to him who accounts anything to be unclean, to him it is unclean.