Remember John’s purpose for writing these “signs” (20:30-31): “Therefore many other signs Jesus also performed in the presence of the disciples, which are not written in this book; but these have been written so that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name.” The result of this miracle is that His disciples (the five men from chapter 1) believed in Him. They had already believed, but for John faith isn’t a “one-time and you’re done” sort of thing. You believe in Christ at the moment of salvation, but you go on believing more and more as you see more of who He is.