How does God begin and complete a good work in believers?

In Philippians 1:6, Paul expresses confidence that the God who began a good work in the Philippians will carry it on to completion until the day of Christ. This emphasizes the assurance that God is the initiator and sustainer of our faith. It is not dependent on human effort; instead, God's faithfulness guarantees the continuation of His work in our lives. This assurance brings comfort to believers, knowing that their salvation and sanctification are securely in His hands, as He grants growth and understanding through His Spirit.