No leaven shall be seen with you in all your territory for seven days; nor shall any of the flesh which you sacrificed the first day at evening be left all night until the morning.
[In celebration of the Passover in future years] seven days shall you eat unleavened bread; even the first day you shall put away leaven [symbolic of corruption] out of your houses; for whoever eats leavened bread from the first day until the seventh day, that person shall be cut off from Israel.
And you shall keep it until the fourteenth day of the same month; and the whole assembly of the congregation of Israel shall [each] kill [his] lamb in the evening.
You shall not offer the blood of My sacrifice with leavened bread [but keep it unmixed], neither shall the fat of My feast remain all night until morning.
He told them another parable: The kingdom of heaven is like leaven (sour dough) which a woman took and covered over in three measures of meal or flour till all of it was leavened. [Gen. 18:6.]