Speaking of the challenges both without and within that Paul faced, N. T. Wright writes:

“Don’t worry about anything,” he [Paul] had written to the Philippians not that long before. That, he knows, is easier said than done; it was always a goal to be striven for, not a permanent condition of smug spirituality.

I’ve often struggled with this verse because I’ve often struggled with worry. With this interpretive insight, the verse becomes an encouragement instead of a demand.

N. T. Wright, Paul: A Biography (New York: Harper Collins, 2018), chap. 12, Kindle.