John Gill Commentary John 6:46

"Not that any man hath seen the Father, save he that is from God, he hath seen the Father." — John 6:46 (ASV)

Not that any man has seen the Father
This is said, lest it should be thought from the above words, that our Lord meant that men should be so taught of God, as that they should visibly see the Father, and vocally hear his voice, and be personally instructed by him; for his voice is not heard, nor his shape seen; see (John 1:18) (5:37) ;

save he which is of God ;
who is begotten of him, and of the same nature and perfections with him, though a distinct person from him, and who was always with him, and lay in his bosom:

he has seen the Father ;
has perfect knowledge of him, personal communion with him; has seen the perfections and glory of his person, and the thoughts, purposes, and counsels of his heart, his whole mind, and will, and all the grace, goodness, and mercy which is in him, and has declared it; see (John 1:18) .