And remember.. parenthetical break in Moses' recital, in view of their shortly having servants of their own.
through. by.
Related Commentaries of Deuteronomy 5:15
Deuteronomy 5:15
15 And remember that thou wast a servant in the land of Egypt, and that the LORD thy God brought thee out thence through a mighty hand and by a stretched out arm: therefore the LORD thy God commanded thee to keep the sabbath day.