1. Assurance during struggle
If we know that salvation began in the purpose of God, then we can be sure it will be completed in the purpose of God. What God starts, he always finishes.
It’s comforting to know that there’s a lot more at stake in your salvation than just you. God saves people, to use Paul’s phrase, for “the praise of his glory” (Ephesians 1:6, 12, 14). That means he has bound up the glory of his name in your salvation. So even when you falter, he’s going to pursue his work in you for the sake of his name.
Every God-seeking Christian I know struggles sometimes with assurance of salvation. You look at your heart and think, Can I really be a Christian and still struggle with that? I’ve done it, too. But if God didn’t choose us because of our goodness, he’s not counting on our goodness to keep us saved. We aren’t chosen because we’re good; we’re chosen because he is. That’s good news for stumblers and strugglers and downright sinners like you and me.