Charles H. Spurgeon on Psalms 110:2

Rule thou in the midst of thine enemies. Set up thy power over them and reign in them. This is a commission to set up a kingdom in the very midst of those who were his enemies; in the hearts of those who had been and were rebellious. His kingdom is set up not by destroying them, but by subduing them, so that they become his willing servants. They yield to him, and he rules over them. It is not here a commission to cut them off, but one much more difficult of execution, —to make them his friends, and to dispose them to submit to his authority. Mere power may crush men; It requires more than that to make rebels willingly submissive, and to dispose them voluntarily to obey. Albert Barnes.