Scripture Focus: Jeremiah 31:33
“I will put my law in their inward parts, and write it in their hearts”.
Scripture does not present the “two covenants” as two different standards of righteousness—one strict and one lenient—but as two different ways people relate to the same unchanging law of God. “The works of his hands are verity and judgment; all his commandments are sure. They stand fast for ever and ever” (Psalm 111:7–8). The shift is not from law to no law; it is from law on stone with self-confidence to law in the heart with Spirit-given power. That’s why the promise of the new covenant is not, “I will relax the law,” but, “I will put my law in their inward parts, and write it in their hearts” (Jeremiah 31:33; Hebrews 8:10).
The Old Covenant: Good Law, Weak Promises
At Sinai, when God spoke His law and wrote it on stone, the people answered, “All that the LORD hath spoken we will do” (Exodus 19:8; 24:7). Their intention was sincere, but heaven heard the flaw: “O that there were such an heart in them, that they would fear me, and keep all my commandments always” (Deuteronomy 5:29). The old covenant, then, is best understood as a human promise resting on human strength. It failed not because God’s law was faulty, but because the people were (Hebrews 8:7–8).
Jeremiah captures God’s grief in the language of a broken marriage: “Which my covenant they brake, although I was an husband unto them, saith the LORD” (Jeremiah 31:32). The problem was never the rule; it was the relationship. Not the standard, but the source. Tablets of stone could tell them what was right, but they could not change their hearts.
Even the way the covenant was ratified points to this: at Sinai, it was sealed with the blood of animals (Exodus 24:7–8)—a shadow pointing forward, but not the substance itself (Hebrews 10:1–4).
The New Covenant: Better Promises, Same Law
Hebrews calls the new covenant “a better covenant, which was established upon better promises” (Hebrews 8:6). Notice: better promises, not a different law. The promises are breathtakingly specific:
- “I will put my laws into their mind, and write them in their hearts…”
- “I will be to them a God…”
- “I will be merciful to their unrighteousness” (Hebrews 8:10–12).
The center of gravity shifts from our “we will” to God’s repeated “I will.”
This new covenant is ratified, not with animal blood, but with Christ’s own: “This cup is the new testament in my blood, which is shed for you” (Luke 22:20). Through His life, death, and priestly ministry, God does what the law alone could never do. “For what the law could not do, in that it was weak through the flesh, God sending his own Son… condemned sin in the flesh: that the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit” (Romans 8:3–4).
Ezekiel describes the same new-covenant work: “A new heart also will I give you, and a new spirit will I put within you… and I will put my spirit within you, and cause you to walk in my statutes” (Ezekiel 36:26–27). God doesn’t only forgive; He transforms. He doesn’t just pardon the lawbreaker; He writes the law in the life.
The Sabbath in the New Covenant
Because the covenant change is about the heart and promises, not a new set of commandments, the Sabbath isn’t abolished under the new covenant—it’s deepened and cherished.
From the beginning, the Sabbath belonged to the Creator: “For in six days the LORD made heaven and earth… and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it” (Exodus 20:11). Later, God tied the Sabbath also to redemption: “Remember that thou wast a servant in the land of Egypt, and that the LORD thy God brought thee out… therefore the LORD thy God commanded thee to keep the sabbath day” (Deuteronomy 5:15). Creation and redemption both meet in this one day.
In the new covenant, those truths move from calendar to heart. We no longer keep the Sabbath to earn favor, but as a sign of what God is doing in us. “Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them” (Ezekiel 20:12). Hebrews agrees: “There remaineth therefore a rest to the people of God” (Hebrews 4:9). That “rest” is both a present faith-rest in Christ and a weekly pledge that His finished work—not our frantic effort—forms the rhythm of our lives. Under the new covenant, we learn to “call the sabbath a delight” (Isaiah 58:13), not a burden.
Two Covenants, Two Experiences
It’s easy to think of the covenants as purely “Old Testament vs. New Testament,” but Scripture shows something deeper. The two covenants are two experiences that can occur in any era.
Paul’s allegory of Hagar and Sarah in Galatians 4 contrasts self-effort with trust in promise. Hagar’s child is born “after the flesh”; Sarah’s child is born “by promise” (Galatians 4:23). The old-covenant experience is trying to fulfill God’s will in our own strength. The new-covenant experience is God fulfilling His will in us by His Spirit.
That’s why Abraham himself—long before Sinai—lived the new-covenant way: “Abraham believed God, and it was counted unto him for righteousness” (Romans 4:3). Paul even says “the scripture… preached before the gospel unto Abraham” (Galatians 3:8).
By contrast, someone today can sit under new-covenant light and still live in an old-covenant mindset—promising, striving, measuring, but not truly trusting the indwelling Christ. It’s possible to keep saying, “All that the LORD hath spoken we will do” while quietly forgetting to ask, “Lord, do in me what I cannot do myself.”
Motive, Power, and Joy
Practically, the difference shows up in motive and power. Under the old-covenant impulse, we grit our teeth and try harder. Under the new, our hearts are changed, and obedience becomes the overflow of love.
“I will run the way of thy commandments, when thou shalt enlarge my heart” (Psalm 119:32). Jesus captures this in one sentence joined to one promise: “If ye love me, keep my commandments. And I will pray the Father, and he shall give you another Comforter” (John 14:15–16). Love provides the why; the Spirit provides the how.
This is why the new covenant never leads to lawlessness. It fulfills “the righteousness of the law… in us, who walk not after the flesh, but after the Spirit” (Romans 8:4). It is also why obedience, under grace, becomes joy instead of drudgery: “I delight to do thy will, O my God: yea, thy law is within my heart” (Psalm 40:8)—a verse the New Testament applies to Christ, and in Christ, to us (Hebrews 10:5–10).
From Tablets to Hearts
So what has truly “changed” is how God’s children relate to His law. In Christ, the covenant shifts:
- From our promises to His presence.
- From commands outside us to character within us.
- From duty as burden to duty as delight.
Revelation sketches the fruit of this relationship in one simple description of God’s final people: “Here are they that keep the commandments of God, and the faith of Jesus” (Revelation 14:12). Not commandments without faith—that would be old-covenant strain. Not faith without commandments—that would be empty profession. But commandments kept because Jesus is trusted, loved, and enthroned in the heart.
If we long to live there, Scripture’s pathway is wonderfully simple and deeply hopeful:
- Return to God with the whole heart (Joel 2:12–13).
- Ask for the Spirit (Luke 11:13).
- Walk in step with Him day by day (Galatians 5:25).
- Rest—in Christ, and in His Sabbath—in the confidence that what He writes, He also empowers.
“For it is God which worketh in you both to will and to do of his good pleasure” (Philippians 2:13). When the covenant moves from tablets to hearts, the same law that once condemned now becomes a melody of grace—and we find ourselves obeying because we want to, because He has made us new.
As you dig into today’s Study Notes, remember: “This book of the law shall not depart out of thy mouth… for then thou shalt make thy way prosperous” (Joshua 1:8). If you’d like practical help to keep Scripture alive…
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