“What was God’s purpose in giving the Law?” is a huge question for Bible teachers. To say that “entire books have been written” about this is, in point of fact, an understatement! Entire interpretive schools have written and taught and lectured and preached all over this question time and time again.
Here are three points to which I hold:
The purpose of the law of God is to show
(1) Each one of us our own sinfulness. Our sinfulness in deed and in thought. Through exposure to the law of God we recognize that we have violated an objective, external law of God. We also come to grips with the fact that we have violated our own internal, subjective senses of that law. There is none righteous, no not one.
(2) Each one of us that we need a Savior, a mediator, One who will take the penalty in our place and keep the law in our place. This mediator was typified in the first law-giver (Moses himself) and also promised through that first law-giver as the True Prophet who was to come (see Exodus 18).
(3) Each one of us the peace and blessing that would be ours if we would love the Lord and our neighbor. The Law is God’s description of the good life (see the Psalmist’s enjoyments in Psalm 119).