What does Paul mean: “To live is Christ”? He begins his explanation in verse 22: “If I am to live in the flesh, that means fruitful labor for me.” But that is a strange explanation: “To live is Christ” becomes “To live is fruitful labor for me.” What is the fruit that comes from Paul’s work? And how is “to live … Christ”? The answers come in verses 24–26.
In verse 22 Paul has said, “If I am to live in the flesh, that means fruitful labor for me. Yet which I shall choose I cannot tell.” Now in verse 24 he says, “To remain in the flesh is more necessary on your account.” So evidently the fruit that Paul’s life produces is not only for himself but is very needful for the sake of the Philippian believers. So the phrase, “For me to live is Christ” now becomes “For me to live is to produce fruit that you all need very much.” Then verse 25 tells us what this fruit is that the church needs and that Paul’s life will produce: “I know that I will remain and continue with you all, for your progress and joy in the faith.” So we can see Paul gradually clarifying what he means by “For me to live is Christ.”
First, it means: My life is dedicated to producing fruit (verse 22). Second, it means: My life is devoted to producing a fruit that is very necessary for you to have (verse 24). Third, it means: My life is devoted to increasing your faith and helping it to overflow with joy (verse 25).
Now the crucial question is: Why in Paul’s mind is it one and the same thing to say on the one hand, “For me to live is Christ,” and to say on the other hand, “My life is devoted to your progress and joy in the faith”? I think those two statements are virtually synonymous for Paul in this context.
John Piper, Don’t Waste Your Life (Wheaton, IL: Crossway Books, 2003), 69–70.