Adam Clarke on Exodus 18:16

I do make them know the statutes of God, and his laws - These words are so very particular that they leave little room for doubt that the law had been given. Such words would scarcely have been used had not the statutes and laws been then in existence. And this is one of the proofs that the transaction mentioned here stands out of its due chronological order; See Clarke's note on Exo 18:5.