Why Was the Gospel of John Written?

“Many other signs truly did Jesus in the presence of His disciples, which are not written in this book: but THESE ARE WRITTEN, THAT YE MIGHT BELIEVE THAT JESUS IS THE CHRIST, THE SON OF GOD; AND THAT BELIEVING YE MIGHT HAVE LIFE THROUGH HIS NAME.” (John 20:30, 3130And many other signs truly did Jesus in the presence of his disciples, which are not written in this book: 31But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name. (John 20:30‑31)).