en_tn/isa/63/12.md

The people of Israel continue speaking.

who made his glorious power go with the right hand of Moses

Here "arm" represents the power of Yahweh. This means it was God's power that enabled Moses to split the Reed Sea. (See: rc://en/ta/man/translate/figs-metonymy)

Like a horse running on flat land, they did not stumble

This means that the people of Israel were sure-footed as horses in open country on their travels toward Israel from Egypt. (See: rc://en/ta/man/translate/figs-simile)