Menachot 55 – Exception Proves the Rule

All flour offerings are kneaded with lukewarm water. Had they used scalding hot water, the offerings would become invalid, and had they used cold water, the dough would be clumpy. Now, however, since they used lukewarm water for best quality, they had to take special care that the dough does not become leavened, and the Kohen would have to continually work the dough to forestall its leavening, for the rule is that all the time that one keeps kneading the dough, it does not leaven.

Even if the remnants of the offering - which are not burned on the Altar but are eaten by the Kohanim - become leavened, one transgresses a negative commandment. Furthermore, one is liable to lashes for working with the leavened offering, whether he it is kneading, shaping, or baking.

The Torah gave a general rule, “Any flour offering shall not be prepared leavened.” Therefore, I would think that there is only one set of punishment for any specific work. Then the Torah stated an exception, “shall not be baked (leavened).” Baking was already included in the rule, so why is it excepted? To make one liable for each individual act. Thus the exception proves, or rather explains, the rule.

Art: E. K. Lautter - Kitchen Still Life Of Vegetables And Preparations For Baking A Cake