A.T. Robertson Commentary John 8:42

"Jesus said unto them, If God were your Father, ye would love me: for I came forth and am come from God; for neither have I come of myself, but he sent me." — John 8:42 (ASV)

Ye would love me (ηγαπατε αν εμε). Conclusion of second-class condition with distinct implication that their failure to love Jesus is proof that God is not their Father (protasis).

For I came forth from God (εγω γαρ εκ του θεου εξηλθον). Second aorist active indicative of εξερχομα, definite historical event (the Incarnation). See 4:30 for εξηλθον εκ. In 13:3; 16:30 Jesus is said to have come from (απο) God. The distinction is not to be pressed. Note the definite consciousness of pre-existence with God as in 17:5.

And am come (κα ηκω). Present active indicative with perfect sense in the verb stem (state of completion) before rise of the tense and here retained. "I am here," Jesus means.

Of myself (απ' εμαυτου). His coming was not self-initiated nor independent of the Father. "But he (εκεινος, emphatic demonstrative pronoun) sent me" and here I am.