Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with the poetry in 6:3-4,7, 9-13.
This chapter record Isaiah's call to prophetic ministry. It recognizes the holiness of God and Isaiah recognizes his need for holiness. (See: [[rc://en/tw/dict/bible/kt/call]] and [[rc://en/tw/dict/bible/kt/prophet]] and [[rc://en/tw/dict/bible/kt/holy]])
The way Yahweh speaks in this chapter shows the inevitability of the punishment of Yahweh against the people of Judah. The punishment must now come. It is too late for repentance. (See: [[rc://en/tw/dict/bible/kt/repent]])