Note 12 at Joh 19:36: John alone mentioned that Jesus' legs were not broken and related that to the fulfillment of the prophecies of Nu 9:12 and Ps 34:20. Breaking the legs of the condemned meant that they could no longer raise themselves up and gasp for air and would therefore die soon (see note 6 at Joh 19:18). Since Jesus was already dead, they didn't break His legs. John saw this as very significant, made special mention of it, and emphasized its importance in helping us believe (Joh 19:35).