New Defender's Study Bible Notes
21:11 Dumah. Dumah was a son of Ishmael (Genesis 25:14) and Seir was a Horite (Genesis 36:20), but both lands became possessions of the Edomites, descendants of Esau, and longtime enemies of Israel. The picture is of Edom calling to the prophet and asking the time of night. As a faithful watchman, Isaiah warns that even though daylight is near, night will come again; the people of Edom urgently need to “return” (Isaiah 21:12) to the God of their father, Isaac.