{I know him} (Egn(936b)a auton). Perfect active indicative with
recitative hoti like quotation marks just before it. This is
one of the pious platitudes, cheap claptrap of the Gnostics, who
would bob up in meetings with such explosions. John punctures
such bubbles with the sharp addition "and keepeth not" (ho m(880a)t(8872)(936e), present active linear participle). "The one who keeps on
saying: 'I have come to know him,' and keeps on not keeping his
commandments is a liar" (pseust(8873), just like Satan,  Joh 8:44 
and like  1Jo 1:8,10 ), followed by the negative statement as in
 1:8,10 . There is a whip-cracker effect in John's words.