63:1-4 Edom was a constant enemy of Israel despite its common ancestry in Isaac (Genesis 25:23). Edom rejoiced at any trouble Israel faced. The imagery in this passage is of a watchman on the wall of Jerusalem, seeing Edom approaching and fearing that the Edomite king in his red garment is leading an attack. But it turns out to be the Lord, in bloodstained clothes, who has trampled and destroyed Edom. Bozrah is a city in Edom. (For other prophecies against Edom, see Amos 1:11, 12; Obadiah 1:10, 11; Malachi 1:2-4.)
63:10 Vexing or grieving the Holy Spirit is willfully thwarting his leading by disobedience or rebellion. Isaiah mentions the work of the Holy Spirit more than any other Old Testament writer. See the note on Ephesians 4:28-32 for more on grieving the Holy Spirit.
63:15–64:7 On behalf of the faithful remnant, Isaiah asks God for two favors: to show mercy and compassion to them and to punish their enemies. Before making these requests, Isaiah recited the Lord’s past favors, reminding him of his compassion in former days (63:7-14).