John 19:35
He who saw this has testified so that you also may believe. His testimony is true, and he knows that he tells the truth — John inserts a direct claim to eyewitness testimony, likely authorial self-reference ("the disciple whom Jesus loved"). The emphatic assertion—"His testimony is true, and he knows that he tells the truth"—defends the water and blood's reality against skeptics. The testimony serves belief: that readers may believe in the reality of Jesus' death and its redemptive significance.