Let’s take the first man as an example of what happened to people who died before the cross. In Gen 5:5 we read, “All the days that Adam lived were 930 years, and he died.” But what happened to Adam after he died? Well, before his death God had told Adam, “By the sweat of your face you shall eat bread, till you return to the ground, for out of it you were taken; for you are dust, and to dust you shall return” (Gen 3:19). So when Adam breathed his last and died, he (Adam) began to return to the dust from which he (Adam) was made. So where is Adam now? Answer: Adam returned to the dust. Since Adam is dust, and dust is without consciousness and “knows nothing,” then it follows that Adam is not conscious of anything. He is not praising God somewhere because dead people - whether they’ve been dead 1 second or 1,000 years - do not and cannot praise God. But is Adam going to remain in this state of death and corruption for all eternity? Not at all!
Because of Jesus’ obedient death on the cross, he was exalted by God to the status of “Lord of all” (Phil 2:8-9; Acts 2:36; 10:36), which includes both those who are dead (or “sleeping”) and those who are alive (Rom 14:9). All people, whether the first human to die or the last human alive, were given to Christ as his inheritance. Thus, both those who died before the cross and those who die after the cross will one day be saved by Christ from every enemy that they need to be saved from so that they may “always be with the Lord,” and so that God may be “all in all.” But I think Scripture is also clear that we won’t be following Jesus to the place where he is now until after he has returned from heaven to receive us to himself, which is still a future event (John 14:1-4; Acts 1:11; 3:21; 1 Cor 15:21-28; 51-54; Phil 3:20-21; 1 Thess 4:13-18).
As for David not ascending to heaven, it’s true that the point Peter and Paul were making is that Jesus - not David - is the Messiah of which David prophesied. But “ascending to heaven” was considered such a big deal to the Jewish people because it was understood by them that those who died didn’t go there. Rather, those who died stayed wherever they were buried or entombed (Acts 2:29; 13:36) - i.e., “Sheol” or the grave. In ascending to heaven rather than staying dead and “asleep” along with everyone else who had died, Jesus was clearly an exception to the rule.
On another thread I posted the following concerning this topic:
As for Elijah, I think it is merely assumed that he was taken to live in what Paul calls the “third heaven” or “paradise,” but I think he was simply caught up into the “first heaven” (i.e., the sky, which is also referred to as “heaven” in Scripture). That is, I believe Elijah was miraculously transported from one place on earth to another, just as God did for Philip (Acts 8:39-40). That the other prophets understood this is evident from the fact that they thought God had “caught him up and cast him upon some mountain or into some valley” (2 Kg 2:16), and thus wanted to go search for him. Elisha, however, evidently knew that God must have hidden Elijah, and thus did not want anyone to go looking for him (v. 18). He did not say they were mistaken for believing that Elijah had been moved to somewhere else on earth; he just thought it would be useless to search for him since it was God himself who had transported him. Moreover, that Elijah was still alive on earth somewhere 13 years after he went up into heaven by a whirlwind seems to be suggested by 2 Chron 21:12, in which we read of a letter that was received from him.
As for Moses and Elijah being seen with Christ at his “transfiguration,” this need only be understood as a vision that was given to Peter, James and John (Mt 17:9): Should we form universalist congregations?.
