Philippians 4:4

Majority Text:
Χαιρετε εν Κυριω παντοτε παλιν ερω, χαιρετε.

KJV:
Rejoice in the Lord always: and again I say, Rejoice.

Comments:
Rejoice…Rejoice: It appears that Paul's point in this verse is to give an emphatic definition to the kind of joy Christians have. So he explains it with modifiers which would be redundant once understood, and without those modifiers once they have been explained.

in the Lord…always: The first characteristic of Christian joy is that it is had in Christ, not in other circumstances. That being understood, the other characteristic of Christian joy is an obvious derivative of the first. That is, if Christian joy were found in circumstances, it would come and go with those circumstances. But since Christian joy is found in Christ, it is as persistent as Christ is faithful. So Christian joy is not simply an emotional outflow of happiness, but a staid contentment in Christ--a conclusion completely in harmony both with the rest of this chapter (for example, verses 11-12) and the rest of the book (for example, chapter 1:20-21).

Expanded Paraphrase:
When you rejoice, do so because of Christ. And since Christ never changes, always rejoice. So you should understand why I say to you without considering any of the often difficult and changing circumstances you face, simply rejoice.