During the period of persecution, God will not abandon the world. He will send two witnesses to announce the coming judgment, similar to how God sent Jonah to Nineveh (Jonah 1:2; 4:11).
Burlap clothing symbolized mourning or repentance (see Genesis 37:34; 2 Samuel 3:31; Nehemiah 9:1; Esther 4:1; Jonah 3:6).