God chose you as the firstfruits to be saved, through sanctification by the Spirit. (2 Thessalonians 2:13)
Dozens of passages in the Bible speak of our final salvation (though not our election) as conditional upon a changed heart and life. The question arises then, How can I have the assurance I will persevere in faith and in the holiness necessary for inheriting eternal life?
The answer is that assurance is rooted in our election (2 Peter 1:10). Divine election is the guarantee that God will undertake to complete by sanctifying grace what his electing grace has begun.
This is the meaning of the new covenant: God does not merely command obedience. He gives it. “The Lord your God will circumcise your heart and the heart of your offspring, so that you will love the Lord your God with all your heart and with all your soul, that you may live” (Deuteronomy 30:6). “I will put my Spirit within you, and cause you to walk in my statutes” (Ezekiel 36:27; cf. 11:20).
Election secures that “those whom [God] justified he also glorified” (Romans 8:30), so that all the conditions laid down for glorification will be met by the power of God’s grace.
Election is the final ground of assurance because, since it is God’s commitment to save, it is also God’s commitment to enable all that is necessary for salvation.