English Standard Version
He who saw it has borne witness--his testimony is true, and he knows that he is telling the truth--that you also may believe.New International Version
The man who saw it has given testimony, and his testimony is true. He knows that he tells the truth, and he testifies so that you also may believe.Catholic Public Domain Version
And he who saw this has offered testimony, and his testimony is true. And he knows that he speaks the truth, so that you also may believe