The spiritual concept of predestination that Paul writes about is controversial. There are many variations in this controversy, but there are basically three major belief systems:
1. Calvinism or Reformed Theology
This belief system purports that God in His sovereignty determines who becomes saved by grace and that there is no human free will involved because the depraved nature of man make him unable to choose. As a result, a person cannot lose their salvation.
This theology was begun in the 1590s by Jacobus Arminius, who died in 1609. In a 1610 declaration, his followers determined that each person has a choice whether to accept or reject Christ. They also said that a person could lose their salvation.
3. Harmonizing Reason and Faith
In the late 1200s, a group of theologians explained predestination as God, knowing everything (sovereignty) and therefore predestining to salvation those whom He knew would choose to accept Christ (free will).
I don’t know about you, but I’m going with #3. I generally agree with much of Arminian thought as opposed to Calvinism but, that said, I’ve read a good many Calvinist/Reformed authors, and I actually agree with a lot of their thinking. The whole “TULIP” thing kind of gets in the way.