What Is Unleavened bread in the Bible?
Food
Flat bread made without yeast. The Jews eat it at Passover, because they left Egypt in haste.
Today
The Host at Mass is unleavened bread.
Where it appears in the Bible
Exodus 12:15; Mark 14:12
What the Bible says
Exodus 12:15
Seven days shall you eat unleavened bread: in the first day there shall be no leaven in your houses: whosoever shall eat any thing leavened, from the first day until the seventh day, that soul shall perish out of Israel.
Mark 14:12
Now on the first day of the unleavened bread, when they sacrificed the pasch, the disciples say to him: Whither wilt thou that we go, and prepare for thee to eat the pasch?
Douay-Rheims Bible (Challoner revision), public domain.
Source: RAE, “ácimo”; Exodus 12:39