According to Paul, all those whom God foreknows, he also predestines. Predestination refers to the particular end for which his elect are chosen–to be conformed to the image of Christ (as spelled out in the final link in the golden chain, glorification–verse 30). Those foreknown are predestined, and those predestined are called. Calling occurs when the gospel is preached, and God’s elect respond to that message with faith.
When Christians speak of the “ordo salutis” we are referring to the “order of salvation.” While we should qualify any discussion of such an “order” by affirming that an omniscient God does not need to do things in sequential order as we do, nevertheless there is a logical order to the way in which God saves us from sin and its consequences. Since we are described as “dead in sin” (Ephesians 2:1-5) and unable to do anything to save ourselves from our dire predicament (John 6:44), God must act upon us while we are still “dead” in order to save us from our sins. The ordo salutis is simply an attempt to understand what actions God takes to save us, and in what logical order he accomplishes them.
This is not an abstract concept because Scripture itself speaks of our salvation as being accomplished for us according to a divinely-ordained progression. The first of these passages is the so called “golden chain” of salvation found in Romans 8:28-30. In that passage Paul writes,
and we know that for those who love God all things work together for good, for those who are called according to his purpose. For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers. And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified.
The passage has been described as the golden chain because Paul not only speaks of an unbreakable order to the plan by which God saves us (the chain), but the apostle is clear that our salvation from beginning to end is the work of a gracious and sovereign God, who having begun the process of our salvation, sees it through to the end (the gold). There is no sense that some of those chosen by God are eventually rejected, or that there is something good within the sinner which moves God to have pity on them and then act on their behalf.
Although Paul reminds his reader that God has the power to turn all things to good (v. 28), he quickly goes on to qualify that this applies to only those who are called according to God’s purpose. Therefore, when the gospel is preached to us, God effectually calls his elect to faith in Jesus Christ. God’s call involves several important elements (i.e., the ordo salutis).
Paul speaks of those foreknown by God as being predestined. Some have erroneously taken this to mean that God looks down the corridors of time and then chooses to save those whom he knows in advance will believe the gospel when it is preached to them.