en_tn_lite_do_not_use/isa/06/08.md

General Information:

Isaiah continues to describe his vision.

the voice of the Lord say

Here "voice" represents the Lord himself. Alternate translation: "the Lord say" (See: rc://en/ta/man/jit/figs-synecdoche)

Whom will I send

It is implied that Yahweh will send someone to speak his message to the people of Israel. Alternate translation: "Whom will I send to be a messenger to my people" (See: rc://en/ta/man/jit/figs-explicit)

who will go for us

It seems "us" refers to Yahweh and the members of his heavenly council to whom he is speaking. (See: rc://en/ta/man/jit/figs-exclusive)