John Calvin Commentary Psalms 110:2

"Jehovah will send forth the rod of thy strength out of Zion: Rule thou in the midst of thine enemies." — Psalms 110:2 (ASV)

Jehovah shall send out of Zion the scepter of your power. The Psalmist not only confirms, in different terms, what he stated above, but also adds that Christ’s kingdom will be vastly extended, because God would make his scepter stretch far and wide. David indeed made several of the surrounding nations tributaries to him, but still his kingdom, when contrasted with other monarchies, was always confined within narrow limits.

There is an implied contrast in the words, as if he had said that Christ should not reign as King on Mount Zion only, because God would cause his power to extend to the remotest regions of the earth. And for this reason it is called the scepter of his power, and it was astonishing that, although the whole world was united in opposition to Christ’s kingdom, it nevertheless continued to spread and prosper.

In a word, David here encourages the godly not to be dispirited by the foolhardy attempts of those who presume to introduce discord and disorder into the kingdom of Christ, for he shows them that God will put forth his invincible power to maintain the glory of his sacred throne.

Therefore, when our minds are troubled by various commotions, let us learn to rely confidently on this support: that no matter how much the world may rage against Christ, it will never be able to hurl him from the right hand of the Father. Moreover, as he does not reign for his own sake, but for our salvation, we may rest assured that we will be protected and preserved from all harm under the protection of this invincible King.

Undoubtedly, our condition in this world involves many hardships. But since it is God’s will that Christ’s kingdom should be surrounded by many enemies—and this is also intended to keep us in a state of constant warfare—we should exercise patience and meekness. Assured of God’s aid, we should boldly defy the rage of the whole world.

From this passage we are instructed about the calling of the Gentiles. For if God had not told us in this place about the extension of Christ’s kingdom, we would not today be counted among his people. But since the wall is broken down (Ephesians 2:14) and the gospel proclaimed, we have been gathered together into the body of the Church, and Christ’s power is put forth to uphold and defend us.