Galatians 4:21-31

The Ugliness of Legalism

Legalism robs you of the blessing of being like Christ. Last time, we saw how the Galatians had exhibited Christlike behavior in receiving Paul as they would receive Jesus Christ. Their love for one another was motivated by their love for Christ. They would have sacrificed their own eyesight for Paul, much like Christ sacrificed His life for us.

But the introduction of legalism risked needing Christ formed again within them. They were missing out on the blessing of sacrificial service to one another. Legalism presents another ugliness: trusting in outward devotion puts you in slavery.

Tell me, you who desire to be under the law, do you not hear the law? For it is written that Abraham had two sons, the one by a bondwoman, the other by a freewoman. But he who was of the bondwoman was born according to the flesh, and he of the freewoman through promise. Which things are symbolic. For these are the two covenants. The one from Mount Sinai, which gives birth to bondage, which is Hagar. For this Hagar is Mount Sinai in Arabia and corresponds to the Jerusalem which now is, and is in bondage with her children. But the Jerusalem above is free, which is the mother of us all. For it is written, “Rejoice, O barren, you who do not bear; break forth and shout, you who are not in labor! For the desolate has many more children than she who has a husband.” Now we, brethren, as Isaac was, are children of promise. But, as he who was born according to the flesh then persecuted him who was born according to the Spirit, even so it is now. Nevertheless what does the Scripture say? “Cast out the bondwoman and her son. For the son of the bondwoman shall not be heir with the son of the freewoman.” So then, brethren, we are not children of the bondwoman but of the free.

Paul shows us that legalism—trusting in outward devotion like circumcision or observing the law—leads to slavery. No one wants slavery, yet going back to trusting works for justification is exactly that.

Two Sons of Abraham: Flesh vs. Promise

Both Ishmael and Isaac were sons of Abraham. For Jews relying on ancestry for salvation, this is significant. Ishmael was born of the flesh; Isaac through promise.

This is a real historical event: Abraham took Hagar because Sarah was barren. But Paul uses it symbolically to trace spiritual lineage to Abraham, to whom the gospel was preached. It reveals the difference between grace and legalism.

God promised Abraham blessings, a great nation, and a child. In Genesis 15:6, Abraham believed God, and it was imputed to him as righteousness.

And he believed in the Lord, and He accounted it to him for righteousness. (Genesis 15:6)

Yet Abraham still took Hagar, producing Ishmael. Later, in Genesis 17, he suggested Ishmael fulfill the promise. This is legalism: trying to fulfill God's promise through human effort, earning favor by works. God said no—salvation is by promise, not flesh.

The comparison is between a child of legalism (Ishmael) and a child of grace/promise/Spirit (Isaac). Legalists seem spiritual, obeying laws to draw closer to God. But they drift further, their outward devotion masking inward sin.

Hearing the Law Rightly

Paul asks: You who desire to be under the law, do you not hear the law? The law (first five books) exposes sin, shows its ugliness, and leads to Christ as schoolmaster.

The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, “In you shall all the nations be blessed.” (Galatians 3:8)

If you believed Moses, you would believe Me, for he wrote about Me. (John 5:46)

The law preaches grace and freedom. Jesus told legalistic Jews that Moses accuses them, pointing to the Messiah.

True Freedom in Grace

Full freedom is doing what makes you happiest eternally, with no lack of opportunity, ability, or desire—all provided by God. Grace creates opportunity, gives ability, and instills desire, yielding joy.

Work out your own salvation with fear and trembling; for it is God who works in you both to will and to do for His good pleasure. (Philippians 2:12-13)

Grace frees you to serve joyfully. How do you receive it? You don't earn it—that's no longer grace. God promised it, igniting faith.

He predestined us to adoption as sons by Jesus Christ to Himself, according to the kind intention of His will, to the praise of the glory of His grace, which He freely bestowed on us in the Beloved. (Ephesians 1:5-6)

Boasting in the Lord

Consider your calling, brethren, that there were not many wise according to the flesh, not many mighty, not many noble; but God has chosen the foolish things of the world to shame the wise... so that no one may boast before Him. But by His doing you are in Christ Jesus, who became to us wisdom from God, and righteousness and sanctification, and redemption, so that, just as it is written, “Let him who boasts, boast in the Lord.” (1 Corinthians 1:26-31)

Legalists boast in works; grace-walkers boast in the Lord: He did it all. Boasting in the Lord acknowledges His work from start to finish.

By the grace of God I am what I am. (1 Corinthians 15:10)

Lord, You will establish peace for us, for You have also performed all our works for us. (Isaiah 26:12)

Identifying and Correcting Legalism

Legalism shows in credit-giving issues (taking credit instead of giving it to God) and reliability issues (not trusting God to fulfill His promises, like Abraham with Hagar).

Rejoice, O barren... (Galatians 4:27)

Cast out the bondwoman and her son. (Galatians 4:30)

Correct it by ceasing outward efforts devoid of inward devotion. Focus on inward reality.

Beware that you do not say in your heart, ‘My power and the might of my hand have gained me this wealth.’ But you shall remember the Lord your God, for it is He who is giving you power to make wealth... (Deuteronomy 8:17-18)

Circumcision is that of the heart, in the Spirit, not in the letter; whose praise is not from men, but from God. (Romans 2:29)

Serve not for men's praise, but God's. Legalists burn out without joy; grace brings strength.

The joy of the Lord is your strength. (Nehemiah 8:10)

Restore to me the joy of Your salvation, and uphold me by Your generous Spirit. Then I will teach transgressors Your ways, and sinners shall be converted to You. (Psalm 51:12-13)

Trust God, pursue Him inwardly. Don't desire slavery—embrace joy in Christ.