For it is the day of the LORD's vengeance, and the year of recompences for the controversy of Zion.

Wesley's Notes

34:8 For - This is the time which God hath fixed, to avenge the cause of his persecuted people.

Jamieson-Fausset-Brown Bible Commentary

8. recompenses for the controversy of Zion-that is, the year when God will retaliate on those who have contended with Zion. Her controversy is His. Edom had thought to extend its borders by laying hold of its neighbor's lands and has instigated Babylon to cruelty towards fallen Judah (Ps 137:7; Eze 36:5); therefore Edom shall suffer the same herself (La 4:21, 22). The final winding up of the controversy between God and all enemies of Him and His people is also foreshadowed (Isa 61:2; 63:4; 66:14-16; Mal 4:1, 3; 2Th 1:7, 8, 9; Re 11:18; 18:20; 19:2).

Matthew Henry's Concise Commentary

34:1-8 Here is a prophecy of the wars of the Lord, all which are both righteous and successful. All nations are concerned. And as they have all had the benefit of his patience, so all must expect to feel his resentment. The description of bloodshed suggests tremendous ideas of the Divine judgments. Idumea here denotes the nations at enmity with the church; also the kingdom of antichrist. Our thoughts cannot reach the horrors of that awful season, to those found opposing the church of Christ. There is a time fixed in the Divine counsels for the deliverance of the church, and the destruction of her enemies. We must patiently wait till then, and judge nothing before the time. Through Christ, mercy is exercised to every believer, consistently with justice, and his name is glorified.