If you know that he is righteous, you know that everyone who practices righteousness is born of him.
"This appears from God's own words, Exodus 19:3-6, c.: Tell the children of Israel Ye have seen what I did to the Egyptians, and how I bare you on eagles' wings, and brought you unto myself. Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people. And ye shall be unto me a kingdom of priests, and a holy nation. Deuteronomy 14:1-2, c.: Ye are the children of the Lord your God-for thou art a holy people to the Lord thy God. In particular, the title of God's Son, even his first-born, was given to the whole Israelitish nation by God himself, Exodus 4:22, chiefly because they were the descendants of Isaac, who was supernaturally begotten by Abraham, through the power which accompanied the promise, Genesis 18:10: Lo, Sarah shall have a son. So St. Paul informs us, Romans 9:7: Neither because they are the seed of Abraham, are they all children (namely of God;) but in Isaac shall a seed be to thee-the children of the flesh, these are not the children of God; but the children of promise are counted for the seed. The apostle's meaning is, that Ishmael and his posterity, whom Abraham procreated by his own natural strength, being children of the flesh, were not children of God; that is, they were not made the visible Church and people of God. But Isaac and his descendants, whom Abraham procreated through the strength which accompanied the promise, being more properly procreated by GOD than by Abraham, were the children of God, i.e. were made the visible Church and people of God, because, by their supernatural generation and title to inherit Canaan, they were a fit image to represent the catholic invisible Church of God, consisting of believers of all ages and nations, who, being regenerated by the Spirit of God, are the true children of God, and heirs of the heavenly country of which Canaan was a type.