en_tn_condensed/deu/04/11.md

General Information:

Moses continues to remind the Israelites of their history.

with fire to the heart of heaven

This is an idiom. "The heart of" means "the middle of" or "the innermost part of," and "heaven" here refers to the sky. Alternate translation: "with a fire that went up to the sky" (See: rc://en/ta/man/jit/figs-idiom)

with darkness, cloud, and thick darkness

Here "thick darkness" describes the cloud. Alternate translation: "with a thick, dark cloud" (See: rc://en/ta/man/jit/figs-hendiadys)

thick darkness

Another possible meaning is "heavy cloud."