New Defender's Study Bible Notes
8:37 If thou believest. This response that Philip gave to the Ethiopian clearly shows that baptism is to be preceded by saving faith in Christ. This truth is also evident from many other Scriptures, but the authenticity of this particular verse has been questioned because of its omission from a number of ancient manuscripts. Either the verse was carelessly omitted by the earliest copyists of the book of Acts, or else some ancient scribe deliberately inserted it, with the error in either case being perpetuated thereby into many later copies. Either could be a possibility, although the latter alternative would seem less probable. In either case, there is no doubt that Philip would have expected a profession of faith from the Ethiopian before he baptized him.