We have already noted that the adverbial phrase to loipon that begins this section means something like "as for the rest [of what needs to be said]." A new section is further indicated by the vocative brothers [and sisters], one of four occurrences in this section (3:13, 17; 4:1). The first and last of these are also accompanied by the familiar my, probably stressing their relationship as friends.
This is the sixth occurrence of the verb rejoice in the letter. It was noted earlier (on 2:17) that for Paul "joy" is primarily a verb, something we do rather than how we feel. The verb itself means to verbalize with praise and singing. Echoing a repeated refrain from the Psalter (e.g., Ps 32:11; 35:9; and many others; cf. Hab 3:18), Paul thus gives this motif perspective. We are to rejoice in the Lord. As with the psalmists, the Lord who saves is both the basis and focus of rejoicing. The phrase in the Lord refers to the ground (or sphere) of our present existence (cf. Phil 2:19, 24) and thus points to our basic relationship with Christ. This in itself should eliminate all attraction to mere religion. Knowing Christ makes trash even of blameless Torah observance; it is unthinkable that under the pressure of present sufferings the Philippians should lose their joy in Christ by yielding to such observance.
In the context of rejoicing in the Lord, Paul begins his warning by noting that what he is about to say he has said many times before (cf. v. 18). That he should have done so in Philippi, where the Jewish contingent was so small it could not even form a synagogue, only underscores the potential threat these itinerants were to every church Paul had established among the Gentiles. Since Philippi straddled the Egnatian Way, the east-west turnpike through Macedonia, this church was always in danger of the Judaizers' showing up with their subversive teaching. So using this letter to warn the Philippians one more timeis "not onerous" (NIV no trouble) to Paul; it is a safeguard for you.
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