2 He was troubled, then, who had power to lay down His life, and had power to take it again. That mighty power is troubled, the firmness of the rock is disturbed: or is it rather our infirmity that is troubled in Him? Assuredly so: let servants believe nothing unworthy of their Lord, but recognize their own membership in their Head. He who died for us, was also Himself troubled in our place. He, therefore, who died in power, was troubled in the midst of His power: He who shall yet transform the body of our humility into similarity of form with the body of His glory, has also transferred into Himself the feeling of our infirmity, and sympathizes with us in the feelings of His own soul.
Accordingly, when it is the great, the brave, the sure, the invincible One that is troubled, let us have no fear for Him, as if He were capable of failing: He is not perishing, but in search of us [who are]. Us, I say; it is us exclusively whom He is thus seeking, that in His trouble we may behold ourselves, and so, when trouble reaches us, may not fall into despair and perish. By His trouble, who could not be troubled save with His own consent, He comforts such as are troubled unwillingly.
Source: Tractates on the Gospel of John (New Advent)