Wherefore then serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator. Wherefore then serveth the law? - If the law does not annul the Abrahamic covenant, and cannot confer salvation on its votaries, why did God give it? This was a very natural objection, and must arise in the mind of any Jew who had paid attention to the apostle's reasoning.
It was added because of transgressions - It was given that we might know our sinfulness, and the need we stood in of the mercy of God. The law is the right line, the straight edge, that determines the obliquity of our conduct. See the notes on Romans 4:15 (note); and especially on Romans 5:20 (note), where this subject is largely discussed, and the figure explained.
Till the seed should come - The law was to be in force till the advent of the Messiah. After that it was to cease.
It was ordained by angels - The ministry of angels was certainly used in giving the law; see Psalms 68:17; Acts 7:53; and Hebrews 2:2; but they were only instruments for transmitting; Moses was the mediator between God and the people, Deuteronomy 5:5.