John Chrysostom

But since His answer met what was in their minds, they add, Now we are sure that Thou knowest all things. See how imperfect they yet were, after so many and great things now at last to say, Now we are sure &c. saying it too as if they were conferring a favour. And needest not that any man should ask thee; i. e. Thou knowest what offends us, before we tell Thee, and Thou hast relieved us by saying that the Father loveth us.

Catena Aurea by Aquinas ↗

Augustine of Hippo

Why this remark? To one Who knew all things, instead of saying, Thou needest not that any man should ask Thee; it would have been more appropriate to have said, Thou needest not to ask any man: yet we know that both of these were done, viz. that our Lord both asked questions, and was asked. But this is soon explained; for both were for the benefit, not of Himself, but of those whom He asked questions of, or by whom He was asked. …

Catena Aurea by Aquinas ↗

Hilary of Poitiers

They believe that He came forth from God, because He does the works of God. For whereas our Lord had said both, I came forth from the Father, and, I am come into the world from the Father, they testified no wonder at the latter words, I am come into the world, which they had often heard before. But their reply shows a belief in and appreciation of the former, I came forth from the Father. …

Catena Aurea by Aquinas ↗

Thomas Aquinas

2166 They profess the certainty of his knowledge when they say, Now we know that you know all things. At first glance, the meaning seems to be that when one clearly explains the things he says, this is a proof of his certain and full knowledge of them: for the sign of one who knows is the ability to fully teach what he knows ‑ "Knowledge is easy for a man of understanding" (Prv 14:6) ‑ and what is beyond one's understanding cannot be plainly told in words. …

Commentary on John ↗