Paul admonishes the Philippian believers toward serving one purpose together. That purpose is to take the mindset of Jesus Christ and to serve one another rather than serving oneself. Believers should think the way that Christ thought, which was to humble Himself so fully that He went from being equal with God and being God, to becoming a man, and not only a man, but a man destined to die a terrible death. All this, Christ did out of obedience to God. He did not hold onto His place in Heaven, but came to earth out of radical obedience and willingly sacrificed Himself. In reward to this obedience, God gave Jesus rulership over the earth. Believers can share in that reward by serving one another in complete humility, by being united, rather than seeking self first. This mindset is in our actual best self-interest. It takes work to have this perspective and act according to it, but such a mindset saves us from conforming to the self-centered way the world thinks. When we do this, God works through us and is pleased with us, which gives us the ultimate fulfillment in life. Rather than complain in the face of difficulty, we can show our identity as children of God by living in contrast to the evil age we’re currently in. If the Philippians live as lights to the world and hold fast to Christ, Paul will get to feel enormous pride when the Day of Judgement comes, because all of his labor for the Philippians’ maturity will have been worth it. They will share the glory and reward of Jesus because of their humble obedience, rather than be put to shame by failing to live out this mindset while on earth and wasting this opportunity to serve God.
Paul tells them he is sending Timothy to teach them, and that Timothy is the only trustworthy minister he knows. Everyone else is preaching for their own selfish gain. If Paul is released from house arrest after his trial, he too will come see the Philippians. Additionally, Epaphroditus, the messenger from Philippi who brought Paul financial support, is returning to the Philippians. He suffered illness on his journey to reach Paul, and nearly died, but has mercifully recovered. Paul holds him up as a man who should be admired by the Philippians because he risked his life in service to Christ.