Galatians 4:23

Now Yahweh visited Sarah as He had said, and Yahweh did for Sarah as He had promised.

nor are they all children because they are Abraham’s seed, but: “through Isaac your seed will be named.”

And you brothers, in accordance with Isaac, are children of promise.

But as at that time he who was born according to the flesh was persecuting him who was born according to the Spirit, so it is now also.

The one who believes in the Son of God has this witness in himself. The one who does not believe God has made Him a liar, because he has not believed in the witness which God has borne witness about His Son.