Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, for it is God who works in you to will and to act in order to fulfill his good purpose. Do everything without grumbling or arguing, so that you may become blameless and pure, “children of God without fault in a warped and crooked generation.” Then you will shine among them like stars in the sky as you hold firmly to the word of life. And then I will be able to boast on the day of Christ that I did not run or labor in vain.
“Work out your salvation with fear and trembling” sounds so intense, so deep — the kind of thing where you’d ask yourself, “What does that even look like? Where would I even start?”
And then Paul follows immediately with “Do everything without grumbling or arguing so that you might be … children of God.” Which is tremendously simple — “That’s it?! Just don’t grumble??”
And that’s the mystery and wonder of the gospel: deep enough to get caught up in wonder and philosophical musings, and yet so practical and tangible. Our faith is never supposed to stay in the theoretical; and sometimes the practical implications are as simple as “Don’t grumble.”