Here "right hand" represents the power of Yahweh through Moses. This means it was God's power that enabled Moses to divide the water of the Reed Sea. (See: [[rc://en/ta/man/translate/figs-metonymy]])
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]])