After greeting the Christians in Philippi (Philippians 1:1-2), Paul expressed his thankfulness (1:3-8) and offered prayer (1:9-11) for them.
3 I thank my God in all my remembrance of you, 4 always in every prayer of mine for you all making my prayer with joy, 5 because of your partnership in the gospel from the first day until now. 6 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. 7 It is right for me to feel this way about you all, because I hold you in my heart, for you are all partakers with me of grace, both in my imprisonment and in the defense and confirmation of the gospel. 8 For God is my witness, how I yearn for you all with the affection of Christ Jesus.
(ESV; all Biblical quotations are from the ESV)
Paul begins by telling his Philippian readers that he thanked God every time that he thought of them and that every time that he prayed for them he did so with joy. Clearly the Philippian church was a favourite of Paul. “Joy” is a key word in Philippians. Paul used the Greek word for it or a form of it sixteen times in the letter.
Paul gives as the reason for his thankfulness the Philippians’ “partnership in the gospel.” By this, he may have been referring to their being part of the Christian fellowship as a result of accepting the gospel or goodnews about Jesus Christ. However, in the light of 4:14-18, I think that he was referring primarily to their sending gifts to him. Their first gifts were sent when he was in Thessalonica, which he’d gone to after his first visit to Philippi. Their latest gifts were sent while he was a prisoner in Rome. Paul may also have been thinking of other things that the Philippians did on behalf of the gospel, such as praying for him (1:19), suffering for the gospel (1:29-30), and witnessing to the gospel by living blameless and harmless lives (2:15-16).
Paul continues by expressing confidence that “he who began a good work in you will bring it to completion at the day of Jesus Christ.” Some commentators think that the “good work” that Paul was referring to was the Philippians’ partnership with him in the gospel as I’ve described it above. However, in light of 2:12-13, others think that it was their salvation, in which case Paul meant that he was sure that God would help the Philippians to grow as Christians until Jesus returned, when their salvation would become complete.
Paul goes on to say that it was right for him to feel or think this way about the Philippians because he had them in his heart for they shared in God’s grace to him. My initial reaction was that by “my grace” Paul thinking of the Philippians’ salvation. However, his saying “inasmuch both in my bonds, and in the defence and confirmation of the gospel” indicates that he was again thinking of the Philippians’ partnership with him in his ministry, which Paul described elsewhere (for example, in Galatians 2:7-9) as God’s grace to him. His using those words may also indicate that he was also thinking of the struggle the Philippians were going through on behalf of the gospel, a struggle similar to what Paul was experiencing (Philippians 1:29-30) and on which Jesus had pronounced a blessing (Matthew 5:11).
So deep is Paul’s affection for the Philippians that he concludes verse 8 by calling on God Himself to bear witness to it.
9 And it is my prayer that your love may abound more and more, with knowledge and all discernment, 10 so that you may approve what is excellent, and so be pure and blameless for the day of Christ, 11 filled with the fruit of righteousness that comes through Jesus Christ, to the glory and praise of God.
Paul prays that the Philippians’ love—the love that God pours into our hearts by the Holy Spirit (Romans 5:5), enabling us to obey the commandments to love God with all our hearts and others as ourselves (Mark 12:30-31)—would be increasingly based on spiritual knowledge and moral insight (compare Colossians 1:9). This would result in their being able to decide what things were best from a variety of possibilities and thus being pure (without evil) and blameless (not stumbling or causing to stumble), filled with the fruit of the Spirit (Galatians 5:22-23). This would bring glory and praise to God (compare John 15:8), which is the ultimate goal of all things.
“The introductory paragraph of 1:3-11, as we have seen, consists of a thanksgiving report (vv. 3-6), a deep, warmhearted statement of the apostle’s concern for the readers (vv.7-8),and an intercessory prayer (vv.9-11). Expressions of thanksgiving, personal affection, supplication, and praise are all closely woven together in a paragraph that introduces the mood and style of what is to come.” (Peter T. O’Brien, The Epistle to the Philippians in The New International Greek Testament Commentary, Grand Rapids, Michigan: William B. Eerdmans Publishing Company, 1991, page 82)