Israel was supposed to do the Law according to God’s command and obey it not to secure redemption but as a means to reflect His glory and draw all the nations to worship the one, true God. When used to this end, the Law could make the old covenant saint rejoice (Deut. 31:9–13; Psalm 119). At the same time, the Israelites were to see their inability to do the Law perfectly and hope for God to remove their transgressions (Isa. 53; Gal. 3:15–29), repenting and offering the prescribed sacrifices to cover their sins temporarily until the coming of the Messiah.
Of course, this was not how everyone in the nation responded to the Torah. Certainly, there were individuals like Samuel, Ruth, and David who understood the Law and lived in line with its purposes. But many lived impenitently and broke the covenant with abandon. The Lord eventually removed them from the Promised Land and brought great destruction upon them for forsaking His law. As we see in today’s passage, it was the repeated, gross, and unrepentant violations of the laws against idolatry and other sins that led to Israel’s exile (Jer. 19).
Being gracious, God brought the people back to their land and gave them another chance to respond properly to His law. Determined to keep the Law so closely that the Lord would never judge them again, most Israelites devoted themselves to the Law with new zeal. Unfortunately, this zeal soon became misdirected. Many treated the keeping of the Law as an end in itself — as a fence to keep the nations away from God as opposed to drawing them — and did not truly return to the Lord (Deut. 30:1–10; Mal. 2:10–16). Some sects added laws and traditions that, if kept, would ensure that the letter of the Mosaic law would not be broken. Over time, the people granted these rules the authority of God’s Word, and therefore many of them failed to recognize the Savior to whom the Law points (Rom. 9:30–33).
Legalism, says Jerry Bridges, is when “we build fences to keep ourselves from committing certain sins. Soon these fences — instead of the sins they were designed to guard against — become the issue. We elevate our rules to the level of God’s commandments” (Transforming Grace, p. 122). Though we know the Savior we must take care lest we respond wrongly to the Law and become legalistic.