John the Apostle
John 6:43ESV·traditional attribution

Jesus answered them, “Do not grumble among yourselves.

John Calvin Reformed @genevareformer

43. Murmur not among yourselves. He throws back on them the blame of the murmuring, as if he had said, “My doctrine contains no ground of offense, but because you are reprobate, it irritates your envenomed breasts, and the reason why you do not relish it is, that you have a vitiated taste.”

Matthew Henry Presbyterian @wholebiblehenry

Whether this conference was with the Capernaites, in whose synagogue Christ now was, or with those who came from the other side of the sea, is not certain nor material; however, it is an instance of Christ's condescension that he gave them leave to ask him questions, and did not resent the interruption as an affront, no, not from his common hearers, though not his immediate followers.

Commenting on John 6:28-59

John Gill Reformed Baptist @doctorgill

No man can come to me,.... That is, by faith, as in Joh 6:35; for otherwise they could corporeally come to him, but not spiritually; because they had neither power nor will of themselves; being dead in trespasses and sins, and impotent to everything that is spiritual: and whilst men are in a state of unregeneracy, blindness, and darkness, they see no need of coming...