Thou shalt break them with a rod of iron - This may refer to the Jewish nation, whose final rejection of the Gospel was foreseen, and in whose place the Gentiles or heathen were brought into the Church of Christ. They were dispossessed of their land, their city was razed to its foundations, their temple was burnt with fire, and upwards of a million of themselves were slaughtered by the Romans! So heavily did the iron rod of God's judgments fall upon them for their obstinate unbelief.
Thou shalt break them with a rod of iron - That is, evidently, thine enemies, for it cannot be supposed to be meant that he would sway such a scepter over his own people. The idea is that he would crush and subdue all his foes. He would have absolute power, and the grant which had been made to him would be accompanied with authority sufficient to hold it. That dominion which was to be conceded to him would be not only one of protection to his friends, but also of punishment on his enemies; and the statement here is made prominent because the former part of the psalm had respect to rebels, and the Messiah is here represented as being invested with power sufficient to punish and restrain them. The Vulgate renders this “thou shalt rule;” the Septuagint, “thou shalt feed - ποιμανεῖς poimaneis that is, thou shalt feed them as a shepherd does his flock; thou shalt exercise over them the care and protection of a shepherd. This rendering occurs by a slight change in the pointing of the Hebrew word, though the most approved mode of pointing the word is that which is followed in our common translation. DeWette, Hengstenberg, Alexander, Horsley, adopt the common reading. What is said in this verse has been urged as an objection to referring it to the Messiah. The remark of DeWette on this matter has been quoted in the introduction to this psalm, Section 4 (3). But it may be observed, while it is everywhere represented that the scepter of the Messiah over the earth will be a mild scepter, it is also everywhere stated that he will ultimately crush and overthrow all his foes.
Thus, in Isaiah 11:4: “He shall smite the earth with the rod of his mouth, and with the breath of his lips shall he slay the wicked.” So Psalm 110:6: “He shall judge among the heathen; he shall fill the places with the dead bodies.” So, likewise, Revelation 19:15: “And out of his mouth goeth a sharp sword, that with it he should smite the nations; and he shall rule them with a rod of iron; and he treadeth the winepress of the fierceness and wrath of Almighty God.” So also in Judges 7:20; Jeremiah 22:28. It is used to denote the crushing of infants on stones, Psalm 137:9. The word “shiver” would well express the idea here - “thou shalt shiver them.”
Like a potter‘s vessel - A vessel or instrument made by a potter; a vessel made of clay. This is easily broken, and especially with a rod of iron, and the idea here is that he would crush and subdue his enemies as easily as this could be done. No image could more happily express the ease with which he would subdue his foes; and this accords with all the representations of the New Testament - that with infinite case - with a word - Christ can subdue his enemies, and consign them to ruin. Compare Matthew 25:41, Matthew 25:46; Luke 19:27. The sense here is, simply, that the Messiah would be absolute; that he would have power to quell all rebellion against God, and to punish all those that rise up against him; and that on those who are incorrigibly rebellious he would exercise that power, and take effectual means to subdue them. This is merely what is done by all just governments, and is by no means inconsistent with the idea that such a government would be mild and gentle toward those who are obedient. The protection of the righteous makes the punishment of the wicked necessary in all governments, and the one cannot be secured without the other. This verse is applied to the Messiah in the Book of Revelation, Revelation 2:27, note; Revelation 19:15, note; compare Revelation 12:5, note (see the notes at these passages).