Theophylact of Ohrid

But My disciples, He says, are not so: rather, whoever among them wishes to be great, let him serve all, because this too is a mark of a great soul — to endure from all and to serve all.

Commentary on Mark ↗

Bede

In which He teaches, that he is the greater, who is the less, and that he becomes the lord, who is servant of all: vain, therefore, was it both for the one party to seek for immoderate things, and the other to be annoyed at their desiring greater things, since we are to arrive at the height of virtue not by power but by humility.

Catena Aurea by Aquinas ↗