Exodus 10:2

and that thou mayest tell in the ears of thy son and of thy son's son what things I have wrought in Egypt, and My signs which I have done among them; that ye may know how that I am the Lord. Since Pharaoh had hardened his heart in the first place, the Lord now gave him up to the doom which he had chosen for himself, and the last plagues had the purpose of completing his obduracy. of this fact Moses was informed, lest he become discouraged. At the same time the Lord had His own glorification in view; for the children of Israel, throughout their generations, should preserve the memory of the Egyptian plagues, in order to keep the fear of the Lord before them all the time.