The New Covenant vs. The Old

Gal. 4:19–31

Introduction

What happens inside the heart of a believer when they try to live the Christian life under the Law instead of as a son or daughter of God? Paul tells us plainly: joy evaporates, bondage returns, and the Christian begins to live like a slave instead of a free child of God.
This is exactly what happened to the Galatians. To expose the danger and rescue them from legalism, Paul turns to a powerful Old Testament picture — the story of Sarah and Hagar — and shows how it illustrates the difference between the Old Covenant and the New.
Before we enter Paul’s argument, it helps to remember how God has worked through covenants throughout Scripture.

Illustration 1: God’s Covenants in Bible
Future events hinge on God’s covenants with His people. An important part of the study of Bible prophecy is based on the interpretation of these divine covenants.
There are 8 important Bible covenants:
Edenic Covenant—Genesis 1:26-28; Genesis 2:15-17.
Adamic Covenant—Genesis 3:14-19.
Noahic Covenant—Genesis 8:21-9:17, 24-27.
Abrahamic Covenant—Genesis 12:1-3.
Mosaic Covenant—Exodus 19:5-8.
Palestinian Covenant—Deut. 28:63-68; Deut. 30:1-9.
Davidic Covenant—2 Samuel 7:4-17; 1 Chron. 17:3-15.
New Covenant—Jeremiah 31:31-34; Hebrews 8:6-13.
All of these Bible covenants—except the Mosaic—are unconditional and eternal. That is, they depend on God, not man, for fulfilment.
Encyclopedia of 15,000 Illustrations: Signs of the Times.

I. Historical Facts Behind Paul’s Illustration
A. Paul’s argument rests on the real historical events of Genesis 12–21. Tracing Abraham’s age helps us see the progression:
Age 75 — The Call and the Promise
God calls Abraham to Canaan and promises him descendants (Gen 12). Sarah is barren, but God delays the fulfillment so the miracle will be unmistakable (Rom 4:16–25).
Age 85 — Human Effort Steps In
Still no child. Sarah suggests Abraham take Hagar. This was culturally acceptable but spiritually disastrous (Gen 16:1–3).
Age 86 — Ishmael Is Born
Hagar conceives, tension erupts, and Ishmael is born (Gen 16:4–16).
Age 99 — God Reaffirms His Promise
God declares that Sarah herself will bear the promised son (Gen 17–18).
Age 100 — Isaac Is Born Isaac (“laughter”) arrives — the child of promise (Gen 21:1–7).
Age 103 — Conflict in the Household
At Isaac’s weaning feast, Ishmael mocks him. God instructs Abraham to send Hagar and Ishmael away (Gen 21:8–14).
On the surface, this is a family drama. Beneath the surface, it is a living illustration of two ways of relating to God — human effort vs. divine promise.

II. The Allegorical Interpretation (Gal. 4:24–27)
Paul is not denying the literal history. He is revealing the spiritual significance embedded in the story.
A. Two Mothers, Two Covenants
Hagar represents the Mosaic Covenant — law, bondage, human effort.
Sarah represents the Abrahamic and New Covenants — promise, grace, supernatural birth.

B. Two Jerusalem’s
Earthly Jerusalem (Hagar): enslaved to Rome and enslaved to the Law.
Heavenly Jerusalem (Sarah): the home of the redeemed, the mother of all who are born by grace.

C. Isaiah 54:1 and the Reversal of Fortunes
Paul applies Isaiah’s imagery of the barren woman to Sarah — and ultimately to the people of God under grace. The one who seemed barren becomes the one with the greater family.

III. The Personal Application (Gal. 4:28–31.
A. Paul now brings the illustration home with three powerful comparisons.

Isaac’s Birth and Our New Birth
Isaac was born supernaturally, by promise.
Believers are born again supernaturally, by the Spirit (John 3:3–5).
Therefore, we must not live like children of bondage.
Ishmael’s Persecution and Legalism’s Opposition
Ishmael mocked Isaac.
Legalists always mock grace.
Paul himself was persecuted by those enslaved to the Law.
Abraham’s Decision and Our Responsibility
Abraham had to cast out the slave woman and her son.
Likewise, believers must decisively reject legalism and those who promote it.
Law and grace cannot coexist as equal systems. One must rule.
Paul ends triumphantly:
We are not children of the slave woman — we are children of the free.
We are heirs of God and co-heirs with Christ (Rom 8:17).
Illustration: James Kraft’s Covenant with God
James L. Kraft, founder of Kraft Foods, once confessed that his early business ambitions left him empty. One day, discouraged, he stopped his pony-drawn cheese wagon and said, “Paddy, we’re not doing this right. Our priorities are wrong. We need to put God first.”
He went home, made a covenant with God, and from that day forward put Christ first in everything. Years later he said, “I would rather be a layman in my church than head the greatest corporation in America. My first job is serving Jesus.”
Kraft learned what Paul is teaching: life works only when grace comes first. —W.A. Criswell

IV. Conclusion
The New Covenant is infinitely superior to the Old. The Law can reveal sin, but it cannot give life. The Law can command, but it cannot empower. The Law can expose bondage, but it cannot produce freedom. To live under the Law when Christ has made us free is not only unnecessary — it is spiritual folly. We are children of the free woman. We are heirs of promise. We are sons and daughters of God. So let us live in the freedom for which Christ has set us free.