(Rom 8:29) For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers.
Whom did God “foreknow”? The word only appears one other time in the Pauline corpus —
(Rom 11:2) God did not reject his people, whom he foreknew. Don’t you know what the Scripture says in the passage about Elijah–how he appealed to God against Israel:
— and it refers to the Jews, concluding that only a remnant of those foreknown by God would be faithful.
We see, here, one sense of God’s foreknowledge. Paul concludes that this remnant — the relatively few Jews who believed in Jesus — is the same remnant referred to in the prophets as being those who will be saved when the long exile is over. God had foreknowledge in the sense that his prophets spoke of these things.
There are, of course, difficult issues with foreknowledge that Christians wrestle with. But for Paul, foreknowledge is not about the paradoxes that might arise due to God knowing in advance. It’s simply the fact that God’s foreknowledge allowed him to announce the results in advance.
Those whom God foreknew are the “remnant” spoken of the prophets, as explained by Paul in some detail in chapters 9 – 11.
“Predestined” is an even more difficult concept, as Paul rarely uses the term — only in 8:29-30 and Eph 1:5, 11. But it should be clear enough from related passages that Paul is speaking of God working out his plan of redemption. Peter preached at Pentecost —
(Acts 2:23) This man was handed over to you by God’s set purpose and foreknowledge; and you, with the help of wicked men, put him to death by nailing him to the cross.
When John and Peter were arrested for preaching the gospel, once they were released, the church prayed,
(Acts 4:27-29) “Indeed Herod and Pontius Pilate met together with the Gentiles and the people of Israel in this city to conspire against your holy servant Jesus, whom you anointed. 28 They did what your power and will had decided beforehand should happen. 29 Now, Lord, consider their threats and enable your servants to speak your word with great boldness.”
The reference to what God “had decided beforehand should happen” is not God’s control of Herod and Pontius Pilate, but his foreknowledge — revealed centuries in the past — that the Jews (as a nation, not each individual) would reject his Messiah and only a remnant would be saved.
Therefore, both foreknowledge and predestiny speak in terms of God’s plan of redemption, revealed by Moses and the prophets.
(Rom 8:30) And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified.
Now, Paul declares, in contrast to the calling and election of the Jews, the church (as a holy nation, not as individuals) has been justified and glorified.
Notice that these are in the past tense. These are accomplished facts. The realization of God’s plan has already been seen. The Gentiles have been justified and grafted into the Jewish root. It’s already happened! Gentiles have already died and been glorified. There is no doubt. God’s plan has come to fruition!
God moved history — peoples, nations, armies, famines, wars — all toward the end that Jesus would come and bring his salvation to the Jews first and also to the Gentiles — on the same terms.