*Fearsome acts (mora gadol), this refers to the appearance of the Divine Presence:* This means that the Holy One appeared in all His glory and smote the first born and then took the Israelites out of Egypt, as is written:"Or has any god ventured to go and take for himself one nation from another by providing prodigious acts, by signs and by portents, by war, by a mighty and an outstretched arm, and awesome power (moraim gedolim)." (Deut. 4:34) Rabbi Yudan says that if you count the letters in the Hebrew verse from the beginning with the first word, lavo, to the word awesome power, moraim, there are seventy two letters. If you think there are seventy-five, so take out the word goy, nation (which refers to Egypt) The number of letters is equal to the number of letters that make up God's great name. The appearance of the Divine presence is alluded to in the verse, "This is my God and I shall glorify Him," (Ex 15) The people of Israel pointed at God's glory when they made this statement. The expressions mora gadol and moraim gedolim refer to the awesome appearance of the Divine Presence. Even though Egypt was filled with idolatry and filth, even so God's presence appeared in Egypt to fulfill the promise made to Jacob, "I shall take you up." God's presence appeared two times in Egypt: first, on the first day of Nisan when God commanded them to prepare for the Passover, and, second, on the night of the redemption from Egypt. Similarly God appeared to them at the Red Sea, as the sages taught: "a humble maid in Egypt saw more at the Red sea than the prophet Ezekiel." Since one who sees the divine presence trembles and is terrified, it is referred to as mora, awesome.