In Philippians 1:6 Paul expresses some radical confidence in the Philippians. He says, “And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus 
Christ.” Paul is absolutely certain that God’s work in the lives of the Philippian church members is going to be perfected. How is that perfection at the day of Christ to be achieved? God will do it. Paul’s confidence is not really in the humans in Philippi, or any human (us) who may read his letter. Paul’s confidence is in God. There could be no certainty if it were dependent on us.
Later on in this letter Paul is going to talk about where his confidence used to be placed before his encounter with Christ. First he had confidence in his circumcision. He now realized that religious rites will serve in no way to give us confidence. Paul also put his confidence in his race; a Jew, descendant of Abraham. He thought this gave him an automatic standing with God. Paul came to realize that certainty can’t be inherited. It comes only from a personal faith in God. Paul also had confidence in the Mosaic Law. He was a Pharisee of the deepest sort. He trusted religious rules for his standing with God. But when He met Christ, he realized how foolish it was to trust in a religious system. As a religious leader of the Jews, Paul had quite a track record. Yet his zeal for Judaism didn’t give him an ounce of assurance. He will say how he strove to obey every detail of the law and was counted perfect among his fellow Jews. But the bottom line was that Paul realized that dedication to the law and rules will only bring bondage and prevent any certainty in a healthy relationship with God. Paul argued that all these things that he used to put his confidence in are nothing but garbage.
Philippians 1:6 is one of the first verses I memorized. I took a course at Detroit Bible College in January 1980 on the book of Philippians. The professor, Greg Hans, still a good friend of mine, required us to memorize certain verses from the book. This verse was the first. As I look back over the 34 years that have passed since that class I’m more confident that ever that it is God that has kept me through it all. It’s not my grip on God that had made the difference but his grip on me. It’s not my goodness I trust in But His. I have no confidence in my Character. I am not confident in my history. I am not confident in my “reverend” persona, or my doctoral degree. I am confident in God’s love. In some ways Philippians 1:6 is the New Testament versions of Jeremiah 29:11. “I know the plans I have for you declares the Lord; plans to prosper you, not to harm you, plans to give you hope and a future.” Hughes writes, “But I am confident in God. I am confident in this word to Lydia and to the jailor and to all the saints in Philippi—and to me: “he who began a good work in you will bring it to completion at the day of Jesus Christ.” This is a promise for every man, woman, and child who turns to Christ, and it is a promise for the great fellowship of the gospel!”