"Finally, my brethren, rejoice in the Lord" (Philippians:3:1)
From Believer’s Bible Commentary by William MacDonald: [Paul] exhorts [his readers] to rejoice in the Lord. The Christian can always find real joy in the Lord, no matter what his circumstances may be. “The source of all his singing is high in the heaven above.” Nothing can really affect his joy unless it first robs him of his Savior, and this clearly is impossible. Natural happiness is affected by pain, sorrow, sickness, poverty, and tragedy. But Christian joy rides high over all the billows of life. Proof of this is found in the fact that Paul gives this exhortation from prison. Surely we can take the advice from such a man as he!