“And there are also many other things which Jesus did, the which, if they should be written every one, I suppose that even the world itself could not contain the books that should be written. Amen.”
But there are also many other things that Jesus did; if every one of them were written down, I suppose that the world itself could not contain the books that would be written. But these are written so that you may come to believe that Jesus is the Messiah, the Son of God, and that through believing you may have life in his name — the Gospel's closing hyperbola (the world could not contain the books) emphasizes the inexhaustibility of Jesus' significance. The infinite surplus of his deeds suggests that no narrative can exhaust his meaning or contain his reality. This volta back to the purpose statement (echoing 20:31) reaffirms that John's Gospel is theological and evangelistic interpretation, not exhaustive chronicle, written to generate faith and eternal life.
Church Fathers on John 21:25
This is the disciple which testifies of these things. When we assert any undoubted fact in common life, we do not withhold our testimony: much less would he, who wrote by the inspiration of the Holy Ghost. And thus the other Apostles, And we are witnesses of these things, and wrote these things. John is only one who appeals to his own testimony; and he does so, because he was the last who wrote. And for this reason he often mentions Christ’s love for him, i.e. to show the…
The which, if they should be written every one, I suppose that even the world itself could not contain the books that should, be written; meaning not the world had not space for them, but that the capacity of readers was not large enough to hold them: though sometimes words themselves may exceed the truth, and yet the thing they express be true; a mode of speech which is used not to explain an obscure and doubtful, but to magnify or estimate a plain, thing: nor does it…