“The angel of the Lord” in the OT is often thought to be a pre-incarnate appearance of Jesus Christ. This is the second time we have “an angel of the Lord” in Acts (the first time is in 5:19). Is it literally an angel, or simply a messenger? With the ongoing emphasis on the Holy Spirit in the passage, it’s probably best to think of this as a divine messenger of some sort rather than a human one.
This passage is a wonderful display of how we are to live our lives as God’s witnesses for the gospel! Philip was sensitive to God’s leading and directing (8:27, 29). He starts a spiritual conversation when he realizes the Ethiopian is seeking God (8:30). He helps the man to understand what the Scripture says about the Messiah (8:35). And finally, he helps the man formalize his belief (8:38).
Acts 8:37 is missing in most modern translations, because it is missing in some of the oldest Greek manuscripts as well as in the vast majority of manuscripts. It was, however, seemingly known to one theologian writing around 200 A.D. (which is actually earlier than almost all of the known Greek manuscripts that we have of the NT). It reads, “Then Philip said, ‘If you believe with all your heart, you may.’ And he answered and said, ‘I believe that Jesus Christ is the Son of God‘” (NKJV). Most believe that it was added to make sure that there was a profession of faith by the Ethiopian before baptism. Even without it, the profession of faith is certainly inferred by his desire to be baptized (since Philip must have talked to him about it while explaining the gospel), but also by the supernatural nature of the passage. God didn’t bring Philip there for no reason. He brought him there so that the Ethiopian could be saved! And that is the final truth about witnessing that we see from this passage. God uses us to share the gospel! Why? We are silly, sinful, and stupid people who continue to mess up. Why use us? I think that it’s because He wants us to experience the blessing that comes from obedience, and the joy that comes from seeing others enter the kingdom.