Paul realized that the first part of this verse might be misunderstood. So he goes on to say, “Though it was not I, but the grace of God that is with me.”
This text does not say that Paul is obeying Christ out of gratitude for grace he had given in the past. It says that, at every moment, the future grace of God enabled Paul’s work.
Does it really say that? Doesn’t it just say that the grace of God worked with Paul? No, it says more. We have to come to terms with the words, “Though it was not I.” Paul wants to exalt the moment-by-moment grace of God in such a way that it is clear that he himself is not the decisive doer of this work.
Nevertheless, he is a doer of this work: “I worked harder than any of them.” He worked. But he said it was the grace of God “toward me.”
If we let all the parts of this verse stand, the end result is this: grace is the decisive doer in Paul’s work. Since Paul is also a doer of his work, the way grace becomes the decisive doer is by becoming the enabling power of Paul’s work.
I take this to mean that, as Paul faced each day’s ministry burden, he bowed his head and confessed that unless future grace was given for that day’s work, he would not be able to do it.
He recalled the words of Jesus, “Apart from me you can do nothing” (John 15:5). So he prayed for future grace for the day, and he trusted in the promise that it would come with power. “My God will supply every need of yours according to his riches in glory in Christ Jesus” (Philippians 4:19).
Then he acted with all his might.