“See what kind of love the Father has given to us, that we should be called children of God; and so we are.” (1 John 3:1).
It is commonplace to hear that ‘we are all children of God’. Certainly, God has created us all in His image, and in that sense we are all His children (Genesis 1:27). When Adam and Eve rebelled against their Father, however, they renounced their heavenly lineage, as do we when we rebel (Genesis 3). At that point, Heaven and Earth diverged (and diverges), so that our physical and spiritual genealogies are no longer identical (John 8; 1 John 3:9-10). Our relationship with the Father must be restored, redeemed, recreated – we must be reborn into His family as spiritual, and not merely physical, beings (John 3:3-8).
This rebirth actually started (and starts) with God, not us; for only He has the power to forgive sin (Matthew 9:1-8; Mark 2:1-12; Luke 5:17-26), and it is He who loves us while we are still sinners (1 John 4:19; Romans 5:8). Israel was the first to be adopted (Exodus 4:22-23), but as a child it was placed under the custody of the law. As Paul explains in his letter to the Galatians, the same is true for us:
“Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed. So then, the law was our guardian until Christ came, in order that we might be justified by faith…I mean that the heir, as long as he is a child, is no different from a slave, though he is the owner of everything, but he is under guardians and managers until the date set by his father. In the same way we also…were enslaved to the elementary principles of the world.” (Galatians 3:23-4:3).
It is only in Jesus Christ that we can be fully reconciled with God; for He is the only begotten Son, whose perfect oneness with the Father was sacrificed so that we might obtain it (John 1:14, 3:16, 17:22-23). In Christ, “the firstborn among many brothers” and "the firstborn of all creation", we can once again trace our ancestry directly to the Father as we are conformed once again to His image (Romans 8:29; Colossians 1:15-23). The spiritual and physical, the Heavenly and the earthly, are thus reunited. As Paul elaborates:
“But now that faith has come, we are no longer under a guardian, for in Christ Jesus you are all sons of God, through faith…[For] when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God…” (Galatians 3:25-4:7; cf. Romans 8:14-17).
According to Paul, to be a “son” of God (i.e. a “brother” of Christ) is to be an “heir” of God (i.e. a “co-heir” of Christ) (Romans 8:17,29; cf. Hebrews 2:10-18). From a Biblical perspective, the word “heir” naturally evokes the “everlasting covenant” given to Abraham, whose line of descent would receive “an everlasting possession” (Genesis 17:7-8). However, Paul – and, elsewhere, Jesus Himself (Matthew 3:9; Luke 3:8) – indicates that genetic ancestry is irrelevant:
“…not all who are descended from Israel belong to Israel, and not all are children of Abraham because they are his offspring…it is not the children of the flesh who are the children of God, but the children of the promise are counted as offspring." (Romans 9:6-8, emphasis added; cf. Romans 4).
Paul expounds this distinction “allegorically”:
“For it is written that Abraham had two sons, one by a slave woman and one by a free woman. But the son of the slave was born according to the flesh, while the son of the free woman was born through promise…Now you, brothers, like Isaac, are children of promise… So, brothers, we are not children of the slave but of the free woman.” (Galatians 4:22-28; cf. 1 Peter 3:5-6).
Despite taking matters into his own hands, Abraham was justified by his belief in God’s promise of offspring, which would eventually include the Messiah (Genesis 15:1-6; cf. Galatians 3:6, 3:16; Romans 4:18-25; Hebrews 11). It was the Messiah, in turn, who originally blessed Abraham in the embodiment of Melchizedek (Genesis 14:17-24). In the same way, if we have faith in Jesus Christ, we become ancestors of Abraham, Isaac, and Jacob – “heirs according to the promise” (Galatians 3:7; Romans 4:6,29). We are thus no longer “children of wrath” (Ephesians 2:3), but are now “children of light, children of the day” (1 Thessalonians 5:5; see also Ephesians 5:8; Philippians 2:14-16); we are, in sum, “free indeed” (John 8:36).
Our status as children of God might seem incongruous with the day-to-day experience of futility, the rampant evils of the world, and, ultimately, the inexorable reality of death. This is where the “heirs” part comes in; for although “the Spirit Himself bears witness with our spirit that we are children of God”, our full inheritance lies in “the glory that is to be revealed in us” – and indeed, in all of creation, including our own bodies (Romans 8:16-17,21, emphasis added). The very glory given to the Son by the Father has also been given – and is being given, and will be given – to all of His children (John 17:22-23; Hebrews 2:10-18). The upshot is that, like the Son Himself, we can dwell in our Father’s house forever (Colossians 1:15; John 8:35; Psalm 23:6). As God made clear in the preamble of His covenant with Abraham, He is our inheritance; He is, that is to say, our “exceedingly great reward” (Genesis 15:1).
