Therefore, why the law? It was added on account of the transgressions, until from whom the seed should come, to whom was promised, having been arranged through messengers by the hand of a mediator, Galatians 3:19.
The promise to the seed was given to Abraham in Genesis 22:17, where God states that the seed of Abraham would possess the gates of his enemies. This seed would come through the line of David to rule over Israel in a kingdom that has no end (2 Samuel 7:12-13).
The Law was then given so that Israel’s transgressions could be dealt with until faith in Christ came. Under the Mosaic Law, through the blood of goats and calves, their sins were covered by means of the sacrifices given to the priest. These gifts and sacrifices could not make the one who offered them mature in regard to their conscience until the time of reformation (Hebrews 9:8). However, the blood of Christ, who offered Himself through the eternal Spirit, cleanses the conscience from dead works so that we are free to serve the living God (Hebrews 9:14).