 Paul is in prison, and having received help from the church in Philippi, he writes a letter to these friends who probably understood his circumstances the same way that we would understand the imprisonment of a leader. Disastrous. Imprisonment halts the leader's work. Imprisonment reflects poorly on the cause. But in his letter, Paul is adamant that God is at work even in this imprisonment, and that the gospel of Christ advances as a direct result of his imprisonment.