I know and am persuaded in the Lord Jesus that nothing is unclean in itself. Still, to someone who considers a thing to be unclean, to that one it is unclean.
However, not everyone has this knowledge. Some have been so used to idolatry up until now that when they eat food sacrificed to an idol, their conscience, being weak, is defiled.
Peter said to them, ‘You know it’s forbidden for a Jewish man to associate with or visit a foreigner, but God has shown me that I must not call any person impure or unclean.