Paul uses one of the most striking biblical allegories in Galatians 4 to expose the danger of returning to the law after receiving the promise. By comparing Ishmael and Isaac, he shows us why grace and legalism can never co-exist. Their lives—and their births—reveal profound truths about the New Covenant. Let’s walk through what this means.
Common misconceptions
Refuting “Now that you are saved, you will have to keep the Law”
Some argue, “We are saved from sin by grace, but now we must live by the law.” In other words, the New Covenant gets us in, but the Old Covenant helps us stay in.
But that’s not true.
Look at the story:
- Ishmael was born of human effort—Abraham trying to help God’s promise along by sleeping with Hagar.
- Isaac was born by faith, a result of believing in what God said, even when it was physically impossible.
What happened after Isaac was born? Did Abraham ever say, “Okay, Isaac, now live like Ishmael”?
Did he call Ishmael back from exile and tell Isaac to learn his ways?
You might think it is absurd, and that’s exactly what it is when you go back into the Law having begun in the Spirit.
That would be like saying, “Now that you’ve received Jesus, go back and live like you’re under Moses.”
Grace doesn’t graduate into law. The promise doesn’t revert to effort. If the fruit is different, it’s because the root is different. We weren’t saved by grace to now perform under law.
That’s spiritual regression.
“Having begun by the Spirit, are you now being perfected by the flesh?” — Galatians 3:3
Refuting “The Anointing that comes and goes”
Isaac wasn’t just a child—it was the child of promise, and Paul tells us that the promise given to Abraham was ultimately about the Holy Spirit (Galatians 3:14).
This matters because people today often say things like, “Does the anointing come and go? Do I need to pray more to keep the Holy Spirit?”
Think about Isaac.
When Isaac was born, was it a seasonal blessing? Did God give him for a time and then take him back?
No. He was the result of God’s word fulfilled.
And to seal that truth, God took Abraham to Moriah to test him—not to revoke the promise, but to prove that He would never back down from it.
The same is true of the Spirit. You don’t receive the Spirit one moment and lose Him the next based on performance. You’re sealed with the Spirit (Ephesians 1:13). You’re not anointed like Saul—under the old covenant. You’re anointed like Jesus, under the new.
Refuting “Fasting and Praying for Promises?”
Some legalists say, “You need to fast and pray more if you want to receive God’s promises.” But let’s be clear:
Fasting and praying is not the price you pay for God’s promises. Faith is.
Abraham didn’t get Isaac by spiritual performance. He got Isaac by believing.
Ishmael was the product of trying to make it happen.
Isaac was the result of letting God do it.
Do you see the difference?
One is birthed in self-effort, the other in resting on God’s faithfulness.
When you fast or pray to earn from God, you’re operating like Abraham with Hagar—producing what God never asked for. But when you fast and pray to align your heart with God’s will, to seek Him, to know Him—that’s life-giving. Just remember: the promise is received, not achieved.
“It is by faith so that it may be in accordance with grace, in order that the promise may be guaranteed.” — Romans 4:16
It’s all about Birth
No matter what Ishmael did, he could never be Isaac. Why?
Because it wasn’t about behavior—it was about birth.
Ishmael was born of a slave; Isaac was born of a free woman.
Ishmael was born of the flesh; Isaac was born of the Spirit.
The same is true for us.
If you are in Christ, you are born of God (John 1:13).
You can’t earn that. You can’t imitate it. And you can’t lose it by performance.
Paul says, “The law is not of faith” (Gal. 3:12).
Why? Because law demands do, while grace invites you to believe.
Once you’re born of the Spirit, you continue in the Spirit. You don’t switch gears into religious performance. Isaac’s life continued in blessing because of who he was, not what he did. (Read more here.)
Cast Out the Bondwoman, the Performance Mindset
Galatians 4:30 is clear:
“Cast out the bondwoman and her son, for the son of the bondwoman shall not be an heir with the son of the free woman.”
You cannot inherit God’s promises through law, effort, or self-righteousness. There is a fundamental incompatibilitybetween grace and law—between faith and works.
So Paul tells us: Get rid of the Hagar mindset.
Stop letting old covenant thinking live in your heart. Kick it out. It has no inheritance with your promise.
Final Word: You Are the Child of the Free Woman
You’re not a slave trying to please a harsh master.
You’re a child of the promise, born of the Spirit, sealed by the Spirit, and led by the Spirit.
So stop acting like you have to earn what Jesus already gave you.
Live in the joy of Isaac—not the burden of Ishmael.
You’re not working to become—you’re resting in who you already are.
“So then, brethren, we are not children of the bondwoman, but of the free woman.” — Galatians 4:31
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