Finally, after Paul developed at length the concepts of Christian humility (the mind of Christ) and heavenly citizenship, he comes to the problem of Euodia and Syntyche, who are either fighting with each other or leaders of two factions within the church fighting with each other. But Paul’s words to them are simple: Be of the same mind in the Lord. That is, remember what the larger picture is, and practice the humility that comes from the mind of Christ; look beyond personal differences and disagreements and feuds.
Syzygus (probably a real name, although all three names—Euodia, Syntyche, and Syzygus—could be baptismal names) is urged to help, and all are reminded of the big picture—their names are written in the book of life and they are co-workers with Paul. Petty feuds have no place in this big picture.
Thus, they are to rejoice “in the Lord.” This is not a platitude to feel good at all times, but a call to root our minds in what’s important. When our mind is focused on “the Lord” (the mind of Christ), we can rejoice, despite our present circumstances, because we know Jesus is the author of all spiritual blessings and good things. He is coming back, and he will take care of those things that make us anxious (often our fights with others).
The antidote to worry and anxiety is prayer. We do not need to “worry” about how someone treated us unjustly. The Lord is near (Paul either means Christ is returning quickly or Christ is present to us) and he will deal with injustices when he comes to judge. Instead of complaints, focus on thanksgiving. The peace of God will then guard your hearts and minds in Christ Jesus, as you await his return.
How can a Christian seek the mind of Christ, the peace of God, and avoid worry and anxiety and things that divide? By thinking about (meditating on) the positive attributes in 4:8-9. There is no reason to understand these things systematically, as if they build on each other. It is a simple list of things we can think about minute by minute that will help us “keep on doing the things that [we] have learned and received and heard and seen” so that the God of peace will be with you. Notice the reference to “peace” from v. 7. The key for Paul in this paragraph is perseverance—to keep on.