If you know that he is righteous, you know that everyone who practices righteousness is born of him.
"2. As the promise, Lo, Sarah shall have a son, which was given to Abraham when he was a hundred years old, and Sarah was ninety, implied that that son was to be supernaturally procreated; so the promise given to Abraham, Genesis 17:5, A father of many nations have I constituted thee, implied that the many nations of believers who, by this promise, were given to Abraham for a seed, were to be generated by the operation of the Spirit of God, producing in them faith and obedience, similar to those for which Abraham was constituted the father of all believers. This higher generation, by which believers have the moral image of God communicated to them, is well described, John 1:12: As many as received him, to them gave he power to be called the sons of God, even to them who believe on his name; οιεγεννηθησαν, who were BEGOTTEN, not of blood, nor of the will of the flesh, nor of the will of man, but of God. That is: Men become the true sons of God, not by their being naturally descended from this or that father, nor by their being called the sons of God by men like themselves, but by God's bestowing on them that high appellation on account of their faith and holiness," (which were produced in them by their regeneration through the Spirit of God.)