And sometimes an infinitive comes before a verb to indicate an obligation in a statement, that it is a mistake to think that it only means it is optional. For instance, when imperatives are restricted against a warning (as will be explained later in Rule 228).

Leviticus 6:23 says,וכל חטאת אשר יובא מדמה אל אהל מועד לכפר בקדש לא תאכל באש תשרף(And no sin-offering, whereof any of the blood is brought into the tent of meeting to make atonement in the holy place, shall be eaten; it shall be burnt with fire).

And Leviticus 10:18 says,הן לא הובא את דמה אל הקדש פנימה אכול תאכלו אתה בקדש כאשר צויתי(Behold, the blood of it was not brought into the sanctuary within; you should certainly have eaten it in the sanctuary, as I commanded).

This is an example of an imperative that is restricted against a warning. The warningלא תאכל*, in Leviticus 6:23, is not to eat the sin offering when the blood of it was brought into the holy place. The imperativeאכול תאכלו, in Leviticus 10:18, is that one must eat the sin offering when the blood of it was not brought into the holy place⁸⁷.*

footnotes: ⁸⁷ Malbim, HaTorah v’HaMitzvah Shemini 57.