Rejoice in the Lord always; again I will say, Rejoice.

Philippians 4:4
Rejoice means to find or experience one’s greatest joy. The important thing to notice is where that joy, is to be found: in The Lord (Christ, Jesus). This joy can be experienced at all times, even in the most difficult of circumstances. It is not to be understood only as happiness. It is more like a sense of great fulfillment or comfort because Christ is near.
你們要因為跟主連結而常常喜樂。我再說，你們要喜樂！腓立比書4:4