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]])
This direct quotation can be stated as an indirect quotation. Alternate translation: "say in their heart that Yahweh will not do anything, either good or evil.
Here "good and evil" is a merism that includes everything in between. Alternate translation: "Yahweh will not do anything at all" (See: [[rc://en/ta/man/translate/figs-merism]])