You also have heard the message of the truth, the gospel of your salvation, and in him you also by your faith have been stamped with the seal of the long-promised holy Spirit
My proud boast is the testimony of my conscience that holiness and godly sincerity, not worldly cunning but the grace of God, have marked my conduct in the outside world and in particular my relations with you.
and not only so, but even we ourselves, who have the Spirit as a foretaste of the future, even we sigh to ourselves as we wait for the redemption of the body that means our full sonship.
He who believes in the Son of God possesses that testimony within himself; he who will not believe God, has made God a liar by refusing to believe the testimony which God has borne to his Son.
meaning that instead of God's children being the children born to him by natural descent, it is the children of the Promise who are reckoned as his true offspring.
'Born of him!' Think what a love the Father has for us, in letting us be called 'children of God!' That is what we are. The world does not recognize us? That is simply because it did not recognize him.
We are children of God now, beloved; what we are to be is not apparent yet, but we do know that when he appears, we are to be like him — for we are to see him as he is.
Here is how the children of God and the children of the devil are recognized; anyone who does not practise righteousness does not belong to God, and neither does he who has no love for his brother.