Offerings: Must Be: Accompanied with Leaven (Yeast)
Source: Nav
Leviticus 7:13
Along with his peace offering of thanksgiving he is to present an offering with cakes of leavened bread.
Amos 4:5
Offer leavened bread as a thank offering, and loudly proclaim your freewill offerings. For that is what you children of Israel love to do,” declares the Lord GOD.