en_tn_condensed/mal/04/03.md

you will trample down the wicked, for they will be ashes under the soles of your feet

Here the victory of God's people is spoken of as if they were walking over the burned bodies of their enemies. (See: rc://en/ta/man/jit/figs-metaphor)

they will be ashes

The Israelites' enemies are spoken of as having been burned to ashes (Malachi 4:1).