Eph. 1:5 - Paul teaches that God “predestined” us in love to be His sons through Jesus Christ. “Predestination” means that God knows what we will do before we do it (it does not mean that God determines what we do; otherwise, we would have no freewill). Predestination is taken from the Greek word “prooridzo” which means to know or declare in advance by God’s foreknowledge. See, for example, 1 Peter 1:2 where Peter writes about the “elect according to the foreknowledge of God.” The terms “predestination” and “the elect” always refer to God’s knowledge (not human knowledge) because God is outside of time (and humans cannot predict the future). There are two types of “predestination,” to grace and to glory. In this verse, Paul is teaching about predestination to grace, which means becoming a Christian.
1 Pet. 1:1-2 – Paul teaches about being destined by God for obedience to Christ. This is another example of predestination to grace. But there is also predestination to glory.
Rom. 8:29-30 – Paul also writes that we are predestined to be conformed to the image of His Son. Now Paul is writing about predestination to glory, which means not only becoming a faithful Christian during our lives, but persevering to the end by conforming our will to Christ’s will.
1 Cor. 15:49 – Paul writes that we are conformed in His image at the resurrection, when we shall bear the image of the man of heaven. These are the people who were predestined to glory.
Rev. 3:5 – Jesus warns that He can blot out the names that are in the book of life. This refers to those currently, not ultimately, justified (those who are predestined to grace, but not to glory). Eph. 1:5; 1 Peter 1:2; Rom. 8:29-30; 1 Cor. 15:49 - therefore, predestination is either to grace (which we could lose) or to glory (which we cannot lose). As alluded to above, some non-Catholics confuse the definition of “predestination” (which means God knows what we will do before we do it) and “predetermination” (the erroneous belief that God determines what we will do). But God does not author evil. We choose evil by our own freewill.