Romans 9 has intimidated more believers regarding predestination than probably any other passage in Scripture. Romans 9:18-21 “Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden. One of you will say to me: “Then why does God still blame us? For who is able to resist his will?” But who are you, a human being, to talk back to God? “Shall what is formed say to the one who formed it, ‘Why did you make me like this?’” Does not the potter have the right to make out of the same lump of clay some pottery for special purposes and some for common use.” (NIV)
Invitations go out first to the few and then to the many. In the first story, the reward is the wages; in the second, the reward is the banquet itself. Both stories seem to focus on people freely choosing or refusing an invitation. So, why would Jesus conclude, “many are invited to be saved, but only few are chosen to be saved?” He wouldn’t. Because, that isn’t the point of these stories.
Predestination is the idea that God chooses who goes to Heaven and who goes to Hell regardless of any human merit, effort or virtue. Calvinism teaches that God must regenerate an individual before she is converted. In other words, before a person can desire to come to Christ and thus truly be saved, her desires must be changed first. And desiring God itself is a gift from God. For a person to really want Christ in their heart, their heart must first be changed to want Christ. (Confused yet?)