what He did to the Egyptian army and horses and chariots when He made the waters of the Red Sea engulf them as they pursued you, and how He destroyed them completely, even to this day;
Because God has made thee as the stars of heaven for multitude (so the preceding chapter concludes), therefore thou shalt love the Lord thy God (so this begins). Those whom God has built up into families, whose beginning was small, but whose latter end greatly increases, should use that as an argument with themselves why they should serve God.
Commenting on Deuteronomy 11:1-7
And what he did unto the army of Egypt, unto their horses, and to their chariots,.... At the Red sea, when they pursued Israel in order to bring them back or destroy them, after they had let them go, which army was very numerous; see Exo 14:7.