Paul saw himself as an accountant (Acts 20:24) who had examined his assets and liabilities and decided to put Jesus Christ ahead of everything else. He had faced this kind of reckoning early in his ministry and had willingly made the spiritual the number one priority in his life (Phil. 3:1–11).
He also saw himself as a runner who wanted to finish his course in joyful victory (Phil. 3:12–14; 2 Tim. 4:8). The three phrases “my life, my course, the ministry” are the key. Paul realized that his life was God’s gift to him, and that God had a special plan for his life that would be fulfilled in his ministry. Paul was devoted to a great Person (“serving the Lord”) and motivated by a great purpose, the building of the church.
Paul’s third picture is that of the steward, for his ministry was something that he had “received of the Lord.” The steward owns little or nothing, but he possesses all things. His sole purpose is to serve his master and please him. “Moreover it is required in stewards that one be found faithful” (1 Cor. 4:2, nkjv). The steward must one day give an account of his ministry, and Paul was ready for that day.
The next picture is that of the witness, “testifying of the Gospel of the grace of God” (Acts 20:24, and note v. 21). The word means “to solemnly give witness,” and it reminds us of the seriousness of the message and of the ministry. As we share the Gospel with others, it is a matter of life or death (2 Cor. 2:15–16). Paul was a faithful witness both in the life that he lived (Acts 20:18) and the message that he preached.
Wiersbe, W. W. (1996, c1989). The Bible exposition commentary. "An exposition of the New Testament comprising the entire 'BE' series"--Jkt. (Ac 20:13). Wheaton, Ill.: Victor Books.