(1) This will be the third time I am coming to you. "By the mouth of two or three witnesses every word shall be established." (2) I have told you before, and foretell as if I were present the second time, and now being absent I write to those who have sinned before, and to all the rest, that if I come again I will not spare—
So reads the law regarding witnesses, as recorded in Deuteronomy 19:15.
In II Corinthians 13, the apostle Paul puts an intriguing twist on this law. Here, two or three witnesses are not different people, but different trips. The"two or three witnesses" are successive trips he made to Corinth. Each separate trip—or more correctly, his teaching during each separate trip—stands as a witness against those who fail to receive correction. Paul's various visits to Corinth provide several witnesses against those who continue to sin.
Notice II Corinthians 13:1-2 from the Berkeley Version:
The message is the witness. Paul understood that, over time, one person can provide a number of witnesses. One person, several witnesses! This understanding has an important application for those of us who labor in the twilight of "this present evil age" (Galatians 1:4). In part, that application is this: The Messiah is to preach the Good News—the gospel—of His Father's Kingdom in two visits; His message will take the form of two separate witnesses. We commonly call them His two ministries or His first and second comings.
History repeats itself. When Christ soon stands to read Isaiah 61:2-3, many, unable to recognize Him as their Messiah, will respond as did the Galileans. At Christ's second "visit," His second witness, many will again be "filled with wrath" and seek to destroy Him (Revelation 19:19).
— Charles Whitaker