Acts 10:14

14. Unclean Even under the patriarchal dispensation the distinction of animals into clean and unclean was religiously established. (Genesis 7:2.) Man, indeed, by nature makes a distinction. Some animals are so repugnant to human tastes and health that we are disgusted at the very thought of eating them. Early in the divine education of man God so used this natural distinction which he had made, as the basis of a moral discrimination, as to impress the minds of fallen men with the difference between the pure and the impure in spirit and life, and between the righteous and the wicked among men. And when God set apart the posterity of Abraham from the idolatries and licentiousness into which the nations were sinking, he made such a distinction of meats as separated Jew and heathen from the same table, and thus struck out one of the most powerful points of union between men. Thus was Israel alone amid the nations; the lonely maintainer of the true God until the time of the God incarnate should come, and then the distinction should be abolished, and all the world be called to the knowledge of Jehovah.

Common or unclean ”One term,” says Grotius, “defines the other. For the swine (Leviticus 11:7) is called unclean, and the same ( 1Ma 10:50 ; 1Ma 10:65 ) is called common, that is, commonly used by Gentiles, a people not sanctified to God. Seneca narrates that ‘In the time of the Emperor Tiberius foreign religious systems were forbidden at Rome, and the test was abstinence from certain animals.’”