en_tn_condensed/psa/077/018.md

thunderous voice

This is personification, referring to the thunder as the voice of God. Alternate translation: "voice, which was as loud as thunder" or "very loud voice" (See: rc://en/ta/man/translate/figs-personification)

lightning lit up the world

This is an exaggeration to emphasize that the lightning lit up everything the writer could see. Alternate translation: "lightning lit up everything as far as you could see" (See: rc://en/ta/man/translate/figs-hyperbole)