'Leaven' in the Bible

‘No grain offering that you bring to the Lord shall be made with leaven, for you shall not offer up in smoke any leaven [which symbolizes the spread of sin] or any honey [which, like leaven, is subject to fermentation] in any offering by fire to the Lord.

As an offering of first fruits you may offer them [leaven and honey] to the Lord, but they shall not go up [in smoke] on the altar as a sweet and soothing aroma.

What is left of it Aaron and his sons are to eat. It shall be eaten as unleavened bread in a holy place; they are to eat it in the courtyard of the Tent of Meeting.

It shall not be baked with leaven [which represents corruption or sin]. I have given it as their share of My offerings by fire; it is most holy, like the sin offering and the guilt offering.

Then Moses said to Aaron, and to his surviving sons, Eleazar and Ithamar, “Take the grain offering that is left over from the offerings by fire to the Lord, and eat it unleavened beside the altar, for it is most holy.

You shall bring in from your places two loaves of bread as a wave offering, made from two-tenths of an ephah of fine flour; they shall be baked with leaven as first fruits to the Lord.