Lost your joy lately due to unexpected circumstances? Our key to maintaining the Joy that Paul writes about in Philippians is totally connected with our relationship with Christ.
Joy is how believers who know Christ and whose futures are guaranteed by Christ respond in the context of present difficulties, not because they like to suffer, but because their joy is “in the Lord.” But joy is not a feeling, it is an activity. In keeping with the Psalmist, Paul urges them to “rejoice in the Lord,” which can only mean to vocalize their joy in song and word. Above everything else, joy is the distinctive mark of the believer in Christ Jesus; and in this letter it comes most often as an imperative. Believers are to “rejoice in the Lord always” (4:4), because joy has not to do with one’s circumstances but with one’s relationship with the Lord; and they are to do so both on their own, as it were, and together with others (2:18). Whatever else, life in Christ is a life of joy. To miss this reality is to miss Philippians altogether; and to miss Philippians at this point is to miss out on an essential quality of Christ life.
Gordon Fee “Paul’s Letter to the Philippians” p53