The continuing work of God in the believers at Philippi was a source of joy to the Apostle Paul. It was the evidence of genuine faith in Christ. He was confident that the work God started in them (justification) would continue (sanctification) right up until the day of Jesus Christ (glorification). The work of justification is a gift of God (Ephesians 2:8, 9) what God does FOR us. The work of sanctification is what God does IN us as we grow in our relationship with Him through Jesus Christ (Ephesians 2:10). Philippians 1:6 is our key text for this study providing the assurance that what God starts, He will finish. We will look at a number of different texts to support the security of the genuine believer.