"And those He predestined, He also called; those He called, He also justified; those He justified, He also glorified" (v. 30).
In theology, we speak of the ordo salutis and the historia salutis. The historia salutis is the history of salvation, and most of the Bible is concerned with it. When we do theology from the perspective of the historia salutis, we consider what Christ our Head has done and what He has been given, and then we consider what we as members of Him participate in. He suffered and was glorified, and in union with Him so have we. He was raised, ascended to heaven, and sits enthroned; in union with Him we have these privileges in essence now, and look forward to their fulness in the world to come. He judges all men, and we in union with Him will also judge the world. This is the way theology is done in terms of the historia salutis.
The ordo salutis is the order of salvation. This focuses on the acts of God and the response of the individual in salvation. God calls us, produces regeneration in us, so that we respond with repentance, faith, and obedience. Behind the divine call is God's electing decree. The ordo salutis is not concerned with a temporal sequence of events, but with a logical order.
Paul provides a condensed form of the ordo salutis in Romans 8:29–30. He tells us that God foreknew certain people and predestinated them to be conformed to the image of His Son. Since God exists in eternity, foreknowledge and predestination are not sequential actions on His part, but logical aspects of His decree. Romans 8:30 says that God called these people to His kingdom, and that those who are called are justified. Since we are justified by faith, we can insert faith between calling and justification. In fact, God's inward call produces regeneration in us, which causes us to cry out in repentance and faith, so that we are justified.
There is no time sequence in this, as if we could be called for a while before we are regenerated, and then live regenerated without having repented, and then we could repent but not turn to Christ, and then finally come to justifying faith. No, they are all logical steps in the same event. When God calls us we are immediately regenerated, and we turn from sin to God in one action, which justifies us. And those who are justified are immediately glorified in the sense of being adopted as children of God.
Coram Deo
The value of _ordo salutis_ theology is that it enables us to see clearly that it is God who saves, freeing us from the sinful tendency to take some credit for our own salvation. We do not proclaim, "I found it," but, "He found me." Rejoice that it is God who is the author and finisher of your faith.