Pour out thy wrath upon the heathen - Punish, as they deserve, the nations that have risen up against thy people, and that have brought; desolation upon the land. The word rendered here pour out is used with reference to a cup or vial, as containing a mixture for the people to drink - of intoxication, or of poison. See the notes at Revelation 16:1; notes at Psalms 11:6; notes at Isaiah 51:17; compare Jeremiah 25:15, Jeremiah 25:17; Matthew 20:22; Matthew 26:39, Matthew 26:42.
That have not known thee - Who are strangers to thee; who are thy enemies. The prayer that the wrath of God might be poured upon them was not because they were ignorant of him, but on account of their wicked conduct toward the people of God. The phrase “that have not known thee” is used merely to designate them, or to describe their character. The prayer is not necessarily a prayer for vengeance, or in the spirit of revenge; it is simply a prayer that justice might be done to them, and is such a prayer as any man may offer who is anxious that justice may be done in the world. See remarks on the imprecations in the Psalms. General Introduction Section 6. It is not proper, however, to use this as a proof-text that God will punish the “pagan,” or will consign them to destruction. The passage obviously has no reference to such a doctrine, whether that doctrine be true or false.
And upon the kingdoms that have not called upon thy name - The people that do not worship thee; referring here particularly to those who had invaded the land, and made it desolate.