{The Spirit and the water and the blood} (	o pneuma kai to
hud(9372) kai to haima). The same three witnesses of verses  6,7 
repeated with the Spirit first. {The three} (hoi treis). The
resumptive article. {Agree in one} (eis to hen eisin). "Are for
the one thing," to bring us to faith in Jesus as the Incarnate
Son of God, the very purpose for which John wrote his Gospel
( 20:31 ).