Leviticus 2:4

"And when thou offerest an oblation of a meal-offering baken in an oven, it shall be unleavened cakes of fine flour mingled with oil, or unleavened wafers anointed with oil. And if thy oblation be a meal-offering of the baking pan, it shall be of fine flour unleavened, mingled with oil. Thou shalt part it in pieces, and pour oil thereon; it shall be a meal-offering, And if thy oblation be a meal-offering of the frying pan, it shall be made of fine flour with oil. And thou shalt bring the meal-offering that is made of these things unto Jehovah: and it shall be presented unto the priest, and he shall bring it unto the altar. And the priest shall take up from the meal-offering the memorial thereof, and shall burn it upon the altar, an offering made by fire, of a sweet savor unto Jehovah. And that which shall be left of the meal-offering shall be Aaron's and his sons': it is a thing most holy of the offerings of Jehovah made by fire."

Whereas the first paragraph described the food-offering as a batch of fine flour, this paragraph describes the offering as having been cooked by one of three different methods: (a) in the oven (Leviticus 2:4), (b) by the baking-pan (Leviticus 2:5), or in a frying-pan (Leviticus 2:7). Interesting as all these different methods of cooking most assuredly were, especially if we could know exactly how each was done, we shall simply pass over them here with the general observation that the meal-offering was also acceptable to God as an oblation when properly cooked. Notice, that despite leaven being often used in cooking, there was to be NO LEAVEN whatever used in connection with an oblation, whether cooked or uncooked. The reason for this lay in the use of leaven as a symbol of corruption or sin. Jesus spoke of the "leaven of the Pharisees," meaning the "false teachings" of the Pharisees. This prohibition regarding leaven was so important that a special mention of it occurs in the very next word of instruction.