The word "he" refers to the enemy king and his army. The great size of the army is spoken of as if they were giant storm clouds. AT: "See, great armies like giant clouds are gathering to attack" or "See, great armies are gathering to attack" (See: [[rc://en/ta/man/translate/figs-simile]])
The enemies' chariots are spoken of as if they were like a storm. Storms can be noisy, destructive, and fast-moving. AT: "the roar of their chariots coming is like a fierce storm" (See: [[rc://en/ta/man/translate/figs-simile]])
This can be stated in active form. AT: "for they will devastate us" or "for they will destroy us all" (See: [[rc://en/ta/man/translate/figs-activepassive]])
This is a warning to the people living in Jerusalem to repent. "Cleanse your heart" is a metaphor for removing evil from their lives. AT: "People of Jerusalem, stop being evil" or "People of Jerusalem, stop living wickedly" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This question is used to rebuke the people for always planning how to sin. AT: "Your deepest thoughts are about how to sin!" or "You are always thinking about how to sin!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
# a voice is bringing news from Dan
Here "a voice" represents a messenger. AT: "a messenger comes and tells about what is happening in Dan" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
# Dan
This probably refers to the region of Dan, which was west of Jerusalem.
# the coming disaster is heard from the mountains of Ephraim
This can be stated in active form. AT: "people hear about the disaster that is coming from Ephraim" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# from Dan ... mountains of Ephraim
By hearing that the the enemies had gotten to Dan and Ephraim, people in Jerusalem would understand that the enemies were getting closer to them.