The difference between a request and a command[1]
אל תאכלו ממנו נא וכו’ ולא תותירו ממנו עד בוקר
Al (Don’t) eat from [the Pesach offering] insufficiently roasted[2]…VeLo (and don’t) leave over any of it until morning[3]
Many times, the Torah uses the word לא, lo (don’t), when it wants to express a negative statement. However, other times it uses the word אל, al (don’t). An example[4] of both is in this week’s parsha, in two adjacent verses. The Torah introduces the mitzvah of the korban Pesach, the Passover offering, with a list of several instructions for its preparation and consumption. All of these instructions constitute individual mitzvos. There’s a mitzvah[5] not to eat a korbon Pesach which wasn’t roasted properly over a fire[6]. Regarding this mitzvah, the Torah uses the word al, when it says not to eat from it insufficiently roasted. There’s another mitzvah[7] not to leave any of the korbon Pesach over until morning[8]. It must be entirely consumed. With this mitzvah, the Torah uses the word lo, when it says don’t leave any of it over. What’s the difference between these two words? Why does the Torah sometimes choose one over the other?