The answer to this question may seem obvious to some on this forum. One may either choose to say that Abraham is either a son of God right now or that he is not. Things may not be quite so simple when one reexamines Lk 20:34-36, however. For now, I want to focus on 20:36:
οὐδὲ γὰρ ἀποθανεῖν ἔτι δύνανται, ἰσάγγελοι γὰρ εἰσιν καὶ υἱοί εἰσιν θεοῦ τῆς ἀναστάσεως υἱοὶ ὄντες.
The text above typed in 'Greek' is made in a context involving certain Sadducees disputing with Jesus about the resurrection from the dead. After these men had posed a 'stumper' for the Christ, he in turn referred them to the Pentateuch, which the Sadducees accepted as authoritative, in order to overturn their fallacious use of Scripture and logic. As one reads Jesus' skilled use of the thornbush account to confute his adversaries, one cannot help but be astounded at his manner of teaching in the face of such formidable opposition.
For instance, Jesus points out that while people in this age marry and are often given in marriage, those whom God deems worthy of the resurrection will neither marry nor be given in marriage. Without trying to explain that perplexing statement, I will move on to Lk 20:34-36.
The context makes it clear that Jesus has Abraham in mind when he exclaims that the children of the resurrection will not be able to die anymore since they will be like angels, being children of God by virtue of the resurrection. A few points now merit our attention.
(1) Luke employs a hapax legomenon (ἰσάγγελοι) that is equivalent to ὡς ἄγγελοι as Matthew 22:30 shows (see Matthew Vellanickal. The Divine Sonship of Christians in the Johannine Writings. Rome: Biblical Institute Press, 1977, page 62).
a) More importantly, however, Luke also utilizes the participial ὄντες which should no doubt be construed as a "causal circumstantial participle here" (NET Bible ftn on Lk 20:36). Vellanickal rightly contends that ὄντες in Lk 20:36 "is very significant" (page 63). We offer full consent to his observation. Yet, one is justified in asking, in what way is this participle highly significant?
b) Vellanickal argues that ὄντες is important in Lk 20:36 because the writer's use of this participial form shows that Jesus is saying it is by virtue of the resurrection that ones such as Abraham, Isaac and Jacob become sons of God: "thus the resurrection becomes the cause and condition of the 'divine sonship' and the 'equality to the angels'"(Vellanickal, 63).
2) The author referenced above ultimately argues that it is only when Abraham and others are resurrected that they truly become children of God "in the full sense of the term." However, to be fair to the author and Luke's text, we must say that Abraham on one level is not a child of God yet; for he has not been raised from the dead. Still, there is a sense in which Abraham must be a child of God already. This is in the sense in that his resurrection has already occurred in the eyes of God. As Jesus exclaimed to the Sadducees: "He is a God, not of the dead, but of the living, for they are all living to him" (Lk 20:38).
a) So while I think it is technically correct to maintain that Abraham is not literally a son of God but only becomes one by virtue of the resurrection from the dead, he is still now a son since Jehovah God will certainly raise Abraham and others from the dead at the divinely appointed time. Abraham evidently became a son of God, in a sense, after he died. This still means that he was not technically one of God's children while he walked the earth. To the contrary, Abraham was one of God's friends, as Scripture indicates (Isa 41:8; James 2:23). In the resurrection, he will assuredly become one of God's earthly sons.
The Gospel by Luke, St [Paperback]