Acts 11:8

But I said, ‘By no means, Lord, for nothing unholy or unclean has ever entered my mouth.’

Romans 14:14

I know and am convinced in the Lord Jesus that nothing is unclean in itself; but to him who thinks anything to be unclean, to him it is unclean.

Leviticus 10:10

and so as to make a distinction between the holy and the profane, and between the unclean and the clean,

Leviticus 11:47

to make a distinction between the unclean and the clean, and between the edible creature and the creature which is not to be eaten.

Ezra 9:11-12

which You have commanded by Your servants the prophets, saying, ‘The land which you are entering to possess is an unclean land with the uncleanness of the peoples of the lands, with their abominations which have filled it from end to end and with their impurity.

Hosea 9:3

They will not remain in the Lord’s land,
But Ephraim will return to Egypt,
And in Assyria they will eat unclean food.

Mark 7:2

and had seen that some of His disciples were eating their bread with impure hands, that is, unwashed.

1 Corinthians 7:14

For the unbelieving husband is sanctified through his wife, and the unbelieving wife is sanctified through her believing husband; for otherwise your children are unclean, but now 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 had seen that some of His disciples were eating their bread with impure hands, that is, unwashed.
Romans 14:14
I know and am convinced in the Lord Jesus that nothing is unclean in itself; but to him who thinks anything to be unclean, to him it is unclean.