Verses 1:2-18 refer to Yahweh's judgment. Verses 1:4-16 describe Yahweh's judgment on the people of Judah.
In verses 1:8-13, Yahweh is speaking. He alternates between using first person and speaking about himself in the third person. (See: [[rc://en/ta/man/translate/figs-123person]])
The people of Judah are spoken of as Yahweh's sacrifice, and the enemy nations are spoken of as his guests who would eat the sacrifice. This can be stated explicitly. AT: "Yahweh has prepared the people of Judah as a sacrifice, and invited the enemy nations as his guests" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-explicit]])
# set apart his guests
Here "set apart" is an idiom that means he has invited them. (See: [[rc://en/ta/man/translate/figs-idiom]])