출애굽기 12:1의 주석

ויאמר ה' אל משה ואל אהרן AND THE LORD SPAKE UNTO MOSES AND AARON — Because Aaron had worked and toiled in performing the wonders just the same as Moses He paid him this honour at the first command by including him with Moses in the communication (Tanchuma Yahshan 2:3:8).

בארץ מצרים לאמר, seeing that this is a paragraph containing a great deal of legislation, it was important to state that this legislation was legislated when the Israelites were still in Egypt. The other commandments of the Torah were communicated to Moses/people either at Mount Sinai, the Tabernacle, or in the wilderness of Moav, shortly before Moses’ death. [there were also some at Marah, on the way to Mount Sinai. Ed.]

וידבר ה' אל משה ואל אהרן בארץ מצרים, “Hashem spoke to Moses and to Aaron in the land of Egypt, etc.” The emphasis here is on the word ארץ, in open country, outside the city limits, as our sages have explained. We must distinguish between such utterances of G’d to Moses as the instruction to warn Pharaoh of the plague of the dying of the firstborn, a communication Moses received while in Pharaoh’s palace, not outside the city limits. Prayers, commandments, etc., G’d had not revealed within the urban area to Moses, nor did Moses offer his prayers, there, as the urban centers were the centers which abounded with idolatrous symbols, symbols which were despicable in the eyes of G’d. In fact, Moses had already been informed about the plague but it had not been a commandment in the sense that he had to deliver the warning at a certain time. This occurred only now, and seeing that there was nothing new in it this warning this could be delivered within the urban area. The legislation about a new calendar and the Passover had to be revealed outside the urban areas of Egypt