Hebrews 2:2

For if the word spoken through angels proved stedfast, and every transgression and disobedience received a just recompense of reward.

The mediation of angels in the giving of the Law of Moses was not stated at that time, the nearest thing to it being found thus: "He came with ten thousands of saints; from his right hand went a fiery law before them" (Deuteronomy 33:2). Paul stated it clearly, saying that the Law "was ordained through angels in the hands of a mediator" (Galatians 3:19); and Stephen also made reference to it, speaking of them "who received the law as it was ordained by angels, and kept it not" (Acts 7:53). The argument is that God's word, although received second or third hand through Moses and angels, was despite that a sacred and binding obligation, not to be despised or set at naught, and was sternly enforced by the imposition of drastic penalties for every infraction or neglect. Many examples of such penalties are recorded in the Old Testament. The sabbath breaker was stoned; Achan was put to death; Saul was rejected from being king; David was not permitted to build the temple; the prophet who did not obey was slain by a lion; and an entire generation perished in the wilderness because of their murmuring and disbelief. Even Moses was restrained from entering the promised land because of his disobedience in striking the rock.