John 20:30-31: Now Jesus did many other signs in the presence of the disciples, which are not written in this book; but these are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in his name.
John 21:25: But there are also many other things which Jesus did; were every one of them to be written, I suppose that the world itself could not contain the books that would be written.
On one hand the Church is told that the Holy Spirit will teach the Church all things, and yet there is the admission in Scripture itself that it does not include everything. The early Church practices and extends its faith with only a partially written account of Christ’s life and teachings. The living tradition of the Church does not replace the biblical testimony, but supplements and helps to interpret it.