{And ye have not known him} (kai ouk egn(936b)ate auton).
Adversative use again of kai="and yet." Perfect active
indicative of gin(9373)k(935c), the verb for experiential knowledge.
This was true of the kosmos ( 1:10  17:25 ) and of the hostile
Jews ( 16:3 ). Jesus prays that the world may know ( 17:23 ) and
the handful of disciples had come to know ( 17:25 ). {But I know
him} (eg(9320)de oida auton). Equipped by eternal fellowship to
reveal the Father ( 1:1-18 ). This peculiar intimate knowledge
Jesus had already claimed ( 7:29 ). Jesus used oida ( 8:19  15:21 ) or gin(9373)k(935c) ( 17:23,25 ) for the knowledge of the
Father. No undue distinction can be drawn here. {And if I should
say} (kan eip(935c)). Third-class condition (concession), "even if I
say," with kai ean (kan) and second aorist active
subjunctive. "Suppose I say." {I shall be like you a liar}
(esomai homoios humin pseust(8873)). Apodosis of the condition.
Homoios (like) is followed by the associative-instrumental case
humin. The word pseust(8873) (liar), in spite of the statement
that they are the children of the devil, the father of lying
( 8:44 ), comes with a sudden jolt because it is a direct charge.
This word liar is not considered polite today in public speech
when hurled at definite individuals. There is a rather free use
of the word in  1Jo 2:4,22  4:20  5:10 . It is not hard to
imagine the quick anger of these Pharisees.