This question emphasizes that bad things will happen then. It can be expressed as a statement. Alternate translation: "The day of Yahweh will certainly be darkness and not light!" or "Bad things, not good things, will certainly happen on the day of Yahweh!" (See: [[rc://en/ta/man/jit/figs-rquestion]])
The words "Will not the day of Yahweh be" is understood from the previous sentence. Like the previous question, it emphasizes that terrible things, not good things, will happen on the day of Yahweh. It can be expressed as a statement. Alternate translation: "It will be a time of when terrible things, not good things, will happen. (See: [[rc://en/ta/man/jit/figs-rquestion]] and [[rc://en/ta/man/jit/figs-parallelism]])