Why was the Law given, and how long was it to remain?
Scripture states the Law was added because of transgressions, until the seed should come to whom the promise was made. It made the whole world responsible and guilty, leaving no excuse for sin, and was ordained by angels in the hand of a mediator.
Les explains that the Law was given so the world would become responsible; before it, people could not be charged with breaking a written Law, but once it came, adultery, thieving, coveting, and all the Ten were clearly sin, leaving no excuse. He points to Galatians 2.19, where the Law was added because of transgressions until the seed should come to whom the promise was made. It was ordained by angels in the hand of a mediator. The Abrahamic covenant promise was spiritual and heavenly, and though Israel broke it repeatedly, God kept it settled and will fulfill it. Les also notes that God is not a three-person mediation; He is mediator, instigator, and fulfiller, alone involved.
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.