Albert Barnes Commentary Psalms 79:1

"O God, the nations are come into thine inheritance; Thy holy temple have they defiled; They have laid Jerusalem in heaps." — Psalms 79:1 (ASV)

O God, the heathen are come into your inheritance - The nations; a foreign people. See Psalms 2:1, note; Psalms 2:8, note; Psalms 78:55, note. The term is one that would be applicable to the Chaldeans, or Babylonians, and the probable allusion here is to their invasion of the holy land under Nebuchadnezzar (2 Chronicles 36:17–21).

Your holy temple have they defiled - They have polluted it by entering it; by removing the sacred furniture; by cutting down the carved work; and by making it desolate. See 2 Chronicles 36:17–18. Compare the notes on Psalms 74:5-7.

They have laid Jerusalem on heaps - See 2 Chronicles 36:19: And they burnt the house of God, and brake down the wall of Jerusalem, and burnt all the palaces thereof with fire, and destroyed all the goodly vessels thereof.