All fowls — Flying things that crawl or creep upon the earth, and so degenerate from their proper nature, and are of a mongrel kind, which may intimate that apostates and mongrels in religion are abominable in the sight of God. Upon all four — Upon four legs, or upon more than four, which is all one to the present purpose.
Related Commentaries of Leviticus 11:20
Leviticus 11:20
20 All fowls that creep, going upon all four, shall be an abomination unto you.