Catena Aurea on John 13:21–30: Augustine of Hippo

This did not come into His mind’then for the first time; but He was now about to make the traitor known, and single him out from the rest, and therefore was troubled in spirit. The traitor too was now just about to go forth to execute his purpose. He was troubled at the thought of His Passion being so near at hand, at the dangers to which His faithful followers would be brought at the hand of the traitor, which were even now impending over Him. Our Lord deigned to be troubled also, to shew that false brethren cannot be cut off, even in the most urgent necessity, without the troubling of the Church. (Tr. lxi. 1.). He was troubled not in flesh, but in spirit; for on occasion of scandals of this kind, the spirit is troubled, not perversely, but in love, lest in separating the tares, some of the wheat too be plucked up with them. (Tr. lx. 5.). But whether He was troubled by pity for perishing Judas, or, by the near approach of His own death, He was troubled not through weakness of mind, but power: He was not troubled because any thing compelled Him, but He troubled Himself, as was said above. And in that He was troubled, He consoles the weak members of His body, i. e. His Church, that they may not think themselves reprobate, should they be troubled at the approach of death.