[21:11] 1 tn The noun דּוּמָה (dumah) means “silence,” but here it is a proper name, probably referring to a site in northern Arabia or to the nation of Edom. See BDB 189 s.v. II דּוּמָה. If Dumah was an area in northern Arabia, it would be of interest to the Edomites because of its strategic position on trade routes which they used. See J. N. Oswalt, Isaiah (NICOT), 1:398.
[21:11] 2 sn Seir is another name for Edom. See BDB 973 s.v. שֵׂעִיר.
[21:11] 3 sn The “night” probably here symbolizes distress and difficult times. See BDB 539 s.v. לַיְלָה.