Deuteronomy 4:39

39.Know therefore this day. He again inculcates what we have lately spoken of, that the glory of the one true God was proved by the miracles, but he does so by way of exhortation. For he desires them carefully and attentively to consider what God had shewn them, because in so plain a matter there would be no excuse for error or ignorance. He therefore infers from what had gone before, that the people must beware of shutting their eyes against the clear revelation of God’s power, and therefore urges them to keep it in memory, because man’s ingratitude is but too prone to forgetfulness. He afterwards reminds them wherefore God would be known, viz., that they might keep His Law and obey His statutes. The sum is, that they would be inexcusable if they did not obediently receive the Law, which they knew to have come from God; for they must needs be worse than stupid if the majesty of God, known and understood by so many proofs, did not awaken them to reverence. And lest they should undervalue the doctrine as proceeding from a mortal man, he expressly confesses, indeed, that he is the minister, and yet that he had set before them nothing which he had not received from God.