“The Lord spoke to Moses and to Aaron in the land of Egypt, saying” (Exodus 12:1). “In the land of Egypt” – why does it not say: “In Egypt”? Rabbi Ḥanina said: The Holy One blessed be He said: It is written in the Torah: “You shall stand outside” (Deuteronomy 24:11).14The debt collector must stand outside and cannot enter the debtor’s house to seize his property. I, too, will do so – “in the land of Egypt,” but not in Egypt.15I.e., within the borders but not in the population centers.
Likewise, Moses said: “As I leave the city” (Exodus 9:29). Rabbi Shimon said: Great is the love for Israel, as the Holy One blessed be He revealed Himself in a place of idol worship, a place of filth, and a place of impurity in order to redeem them. This is analogous to a priest whose teruma fell into a cemetery. He says: What shall I do?
To impurify myself is impossible, and to leave my teruma there is impossible. It is preferable that I render myself impure one time and then purify myself, and [thus] I will not lose my teruma. So, our ancestors were the teruma of the Holy One blessed be He, as it is stated: “Israel is holy to the Lord, [the first of His crop]” (Jeremiah 2:3).16Teruma is also described as the first of a crop (see Deuteronomy 18:4).
They were among the graves, as it is stated: “As there was no house in which there were none dead” (Exodus 12:30), and it says: “And Egypt was burying [those whom the Lord had smote]” (Numbers 33:4). The Holy One blessed be He said: How do I redeem them? To leave them there is impossible. It is preferable to come down and redeem them, as it is stated: “I came down to deliver them from the hand of Egypt” (Exodus 3:8).
When He took them out, He summoned Aaron, and he purified Him, as it is stated: “He shall atone for the Holy of Holies [mikdash hakodesh]” (Leviticus 16:33), “He shall atone for the Sanctuary [hakodesh]” (Leviticus 16:16).17Hakodesh is homiletically understood to refer to the Source of sanctity.