Charles Spurgeon Commentary Galatians 3:18

"For if the inheritance is of the law, it is no more of promise: but God hath granted it to Abraham by promise." — Galatians 3:18 (ASV)

For if the inheritance be of the law, it is no more of promise:

God gave it to Abraham by promise. It was a free gift; He did not bestow it upon the condition of merit on Abraham's part. Isaac was born, not according to the power of the flesh, but according to promise, and the whole covenant is according to free grace and divine promise.

For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.

All through the Book of Genesis, it is promise, promise, and promise. Isaac was an heir of the promise, and Jacob was an heir of the promise. In fact, Isaac was born by promise, and Ishmael the elder brother did not inherit the blessing because he was born after the flesh. Those who believe in Christ are heirs according to the promise. Now, a promise takes us out of the region of law.

For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.

So, then, we know it is by promise, and God must keep his promise, and we must believe it. It must be true; and if we do believe it, we will prove it to be true, and it will be fulfilled in every jot and tittle to every believing soul.