“What purpose then does the law serve? It was added because of transgressions, till the Seed should come to whom the promise was made; and it was appointed through angels by the hand of a mediator.”

God gave the law to show where people transgress His standards. 

What purpose then does the law serve?

Paul now turns again to the purpose of the law (Ga 3:19-25).

It was added because of transgressions,

God gave the law to identify when a person crosses the line of His standards. “Transgression” is stepping across a line, disobeying an explicit command. The law reveals God’s character. The purpose of the law is to show people that they more than missed the mark of God’s holiness but that they stepped across an obvious line in doing so. People crossed a line into the prohibited territory by adding works to salvation.

Sin was always sin, but the law made it a transgression. Murder was always a sin, but it did not become a transgression until God put it into the Ten Commandments. It would be impossible to play a football game without lines marking certain boundaries. The law defines who and what God is. 

God never intended the law to annul His unconditional covenant or promise. God annexed the law to serve His covenant of grace. It never added anything to grace. It serves grace by showing that people cannot earn or deserve any merit before God, for they have already crossed God’s standards.

“Moreover the law entered that the offense might abound. But where sin abounded, grace abounded much more…” (Romans 5:20).

till the Seed should come to whom the promise was made;

The law temporarily served the purpose of showing Israel’s transgressions until the Messiah came (the “Seed”). Failure to keep the law shows their need for a Savior.

and it was appointed through angels

“Appointed” denotes ideas of to arrange, set in order, or prescribe. The law has two mediators: angels and Moses. First, the angels gave Moses the law; then Moses gave Israel the law. Both brought precise descriptions of sin to Israel.

by the hand of a mediator

The mediator here is “Moses.” God gave the Abrahamic covenant without a mediator because that covenant was a unilateral contract, not bilateral. God was the only person who established the provisions of grace. The Mosaic law required mediators because it was bilateral (Deuteronomy 5:33)–mankind had a part, and God had a role. Mankind’s function was to obey, and God’s part was to bless. The kink in the armor was humanity couldn’t keep its part of the bargain.

Principle:

The purpose of the law is to show us our desperate need for the Savior.

Application:

The purpose of the law is to show us our desperate need for a Savior, our need for grace. The law cannot give us what grace can give us. The law cannot save souls.

God gave the law to show sin in its true light. It shows the violation of God’s laws and, thus, of God’s character. The law does not make people sinners but transgressors.

It is essential to know why God gave the law so we do not misuse or abuse it. If you know the purpose of iodine, you will not drink it! The law will curse us if we misuse it. If we use the law to bring ourselves to heaven, it will land us in hell. If we depend on ourselves for salvation, God will prosecute us to the full extent of the law. The law puts the skull and crossbones on the bottle of poison.

The law is like a mirror that reveals our dirty face so we can wash it in the blood of Christ. We do not wash our face with the mirror; that is not the purpose of a mirror. The purpose of the law is to show us that we are morally bankrupt; therefore, we need a Savior.