This is an idiom. Here silence is meant to signal shock and amazement. Alternate translation: "Be shocked" (See: [[rc://en/ta/man/translate/figs-idiom]])
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. Alternate translation: "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]])