John Gill Commentary John 7:28

"Jesus therefore cried in the temple, teaching and saying, Ye both know me, and know whence I am; and I am not come of myself, but he that sent me is true, whom ye know not." — John 7:28 (ASV)

Then cried Jesus in the temple as he taught
Overhearing the reasonings of these men, however, knowing what they said; so the Persic version adds, "having secretly known this"; exalted his voice as he was teaching in the temple, and in the midst of his discourse, publicly before all the people, in the temple, spoke out with a loud voice, that all might hear:

saying, you both know me, and you know from where I am ;
some, as the Ethiopic version, read these words by way of interrogation, "do you both know me, and do you know from where I am?" no; you do not. Or they may be considered as an ironical concession; yes, you know me, and you know from where I am; you know me to be Jesus of Nazareth, but you are wrong, I am not of Nazareth; you suppose I come, from Galilee, but that is your ignorance; you take me to be the real son of Joseph, to be begotten by him on Mary, but that is your mistake: such is your knowledge of me: you know me indeed who I am, and from where I come.

And I am not come of myself ;
into this world, by incarnation, or the assumption of human nature, to work out the salvation of men; the Father called him to it, and he agreeing to do it, was in the fulness of time sent about it; this was not a device of his own, or an honour he took to himself; he was not alone in it; it was a mutual agreement between him and his Father, in consequence of which he was sent and came.

But he that sent me is true ;
to the covenant he made with Christ, and to the promises he made to the fathers of the Old Testament, concerning the mission of his Son; and he is true to be believed, in the testimonies he gave of him, particularly by a voice from heaven, declaring him his beloved Son.

Whom you know not ;
so that notwithstanding all their boasted knowledge of him, they knew not his Father, from where he came, and by whom he was sent; and notwithstanding also their boasted knowledge of the one, only, true, and living God, see (Romans 2:17) ; yet they knew him not in a spiritual sense; they knew him not in Christ, nor as the Father of Christ; they knew neither the Father nor the Son: and this their ignorance of both was the reason of their hatred of Christ, and of his followers, (John 15:21) (16:3) .