it is more likely that much-disputed
v. 21 refers to Yahweh taking priests and Levites from among the nations in v.
19. This is apparent for a number of reasons. First, it is the nations who are
the main actors in vv. 18-21. Form them (מהם [v. 19]) are taken
"survivors" whose mission it is to tell of Yahweh's glory to the
remaining nations. They will bring the dispersed Israelites from among the
nations (v. 20). Verse 21 then goes on to state that also from them (גם מהם),
i.e. also from these nations, he will take priests and Levites. The presence of
the particle גם suggests that Yahweh is taking from a group form which he has
already taken, i.e. the nations referred to in vv. 18-19. (P.A. Smith, Rhetoric
and Redaction in Trito-Isaiah: The Structure, Growth and Authorship of Isaiah
56-66 [Supplements to Vetus Testamentum 62; Leiden, Brill: 1995], 168)