Leaven (Yeast): Leavened Bread Used with a Wave-Offering
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Leviticus 23:15–17
From the day after the Sabbath, the day you brought the sheaf of the wave offering, you are to count off seven full weeks. / You shall count off fifty days until the day after the seventh Sabbath, and then present an offering of new grain to the LORD. / Bring two loaves of bread from your dwellings as a wave offering, each made from two-tenths of an ephah of fine flour, baked with leaven, as the firstfruits to the LORD.