# Then your light would be broken open like the sunrise

This means that if they help people in need, their deeds will be like lights others will see, as when the sun comes up after a dark night. Or the light may refer to the light of the Lord, shining on them and blessing them.

# your healing would quickly sprout up

This means God will bless and restore them quickly, as a wound heals quickly.

# your righteousness would go before you, and the glory of Yahweh would be your rearguard

This refers to the time when God protected the people of Israel as they escaped from Egypt. This means God will again protect them from their enemies if they will do what is right.