Eastern Fathers
John Chrysostom
Now they went about in the public place: with boldness they attacked even the market, and in the midst of enemies they prevailed, and that saying was fulfilled, "Be Thou Ruler in the midst among Thine enemies." This was a greater miracle, that they, arrested, cast into prison, should do such acts as these!
Homily on Acts 12 ↗
Western Saints
Augustine of Hippo
And what followeth? "The Lord shall send the rod of Thy power out of Sion." It appeareth, brethren, it most clearly appeareth, that the Prophet is not speaking of that kingdom of Christ, in which He reigneth for ever with His Father, Ruler of the things which are made through Him: for when doth not God the Word reign, who is in the beginning with God? For it is said, "Now unto the King eternal, immortal, invisible, the only wise God, be honour and glory for ever and ever." To what eternal King? To one invisible, incorruptible. …
Exposition on Psalm 110 ↗
Jerome
The Lord shall send forth the rod of your power out of Sion. "The rod." In the Hebrew it has not so much "rod" as "scepter," that is, the emblem of royal power. The Lord shall send forth the rod of your power out of Sion. "For out of Sion shall go forth the law, and the word of the Lord out of Jerusalem." Rule in the midst of your enemies. He did not say, Kill your enemies. But what? Rule in the midst of your enemies. Make your enemies, who had been strangers, begin to be yours. Rule in the midst of your enemies. …
Homily 36, on Psalm 109 ↗
Bonaventure
Under the Law in the mystery of the giving of the Law, Christ is symbolized by Moses' staff with which he chastised the Egyptians and dried up the sea, and which is the scepter of power which the Lord stretched forth from Sion.
Collations on the Hexaemeron, Collation 14 ↗