Church Fathers on John 11:39

Christ did not answer Mary, as He had her; sister, on account of the people present. In condescension to them He humbled Himself, and let His human nature be seen, in order to gain them as witnesses to the miracle: When Jesus therefore saw her weeping, and the Jews also weeping which came with her, He groaned in His spirit, and was troubled.

For who but Himself could trouble Him? Christ was troubled, because it pleased Him to be troubled; He hungered, because it pleased Him to hunger. It was in His own power to be affected in this or that way or not. The Word took up soul and flesh, and whole man, and fitted it to Himself in unity of person. And thus according to the nod and will of that higher nature in Him, in which the sovereign power resides, He becomes weak and troubled.

To prove His human nature He sometimes gives it free vent, while at other times He commands, and restrains it by, the power of the Holy Ghost. Our Lord allows His nature to be affected in these ways both to prove that He is very Man, not Man in appearance only; and also to teach us by His own example the due measures of joy and grief. For the absence altogether of sympathy and sorrow is brutal, the excess of them is womanly.