And because ye are sons… – Galatians 4:6

Adoption gives us the rights of children, regeneration gives us the nature of children: we are partakers of both of these, for we are sons. Let us here observe that this sonship is a gift of grace received by faith. We are not the sons of God by nature in the sense here meant. We are in a sense “the offspring God” by nature, but this is very different from the sonship here described, which is the peculiar privilege of those who are born again. The Jews claimed to be of the family of God, but as their privileges came to them by the way of their fleshly birth, they are likened to Ishmael, who was born after the flesh, but who was cast out as the son of the bondwoman, and compelled to give way to the son of the promise. We have a sonship which does not come to us by nature, for we are “born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.” Our sonship comes by promise, by the operation of God as a special gift to a peculiar seed, set apart unto the Lord by His own sovereign grace, as Isaac was. This honour and privilege come to us, according to the connection of our text, by faith. Note well the twenty-sixth verse of the preceding chapter: “For ye are all the children of God by faith in Christ Jesus.” As unbelievers we know nothing of adoption. While we are under the law as self-righteous we know something of servitude, but we know nothing of sonship. It is only after that faith has come that we cease to be under the schoolmaster and rise out of our minority to take the privileges of the sons of God. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1435.cfm