John Chrysostom — as excerpted in the Catena Aurea on Matthew 26:39-44

“That He prays for this a second and a third time, comes of the feelings belonging to human frailty, through which also He feared death, thus giving assurance that He was truly made man. For in Scripture when any thing is repeated a second and third time, that is the greatest proof of its truth and reality; as, for example, when Joseph says to Pharaoh, And for that thou sawedst it twice, it is proof of the thing being established by God. (Gen. 41:32.)”