'Leaven' in the Bible
Seven days shall ye eat unleavened bread: on the very first day ye shall put away leaven out of your houses; for whoever eateth leavened bread from the first day until the seventh day that soul shall be cut off from Israel.
Seven days shall there be no leaven found in your houses; for whoever eateth what is leavened that soul shall be cut off from the assembly of Israel, whether he be a sojourner, or born in the land.
Unleavened bread shall be eaten the seven days; and leavened bread shall not be seen with thee, neither shall there be leaven seen with thee in all thy borders.
Thou shalt not offer the blood of my sacrifice with leaven; neither shall the sacrifice of the feast of the passover be left over night until the morning.
No oblation which ye shall present to Jehovah shall be made with leaven; for no leaven and no honey shall ye burn in any fire-offering to Jehovah.
It shall not be baken with leaven. As their portion have I given it unto them of my offerings by fire: it is most holy; as the sin-offering, and as the trespass-offering.
Out of your dwellings shall ye bring two wave-loaves, of two tenths of fine flour; with leaven shall they be baken; as first-fruits to Jehovah.
And there shall be no leaven seen with thee in all thy borders seven days; neither shall any of the flesh, which thou sacrificedst at even on the first day, be left over night until the morning. --
and burn a thank-offering with leaven, and proclaim, publish, voluntary offerings: for this pleaseth you, children of Israel, saith the Lord Jehovah.
He spoke another parable to them: The kingdom of the heavens is like leaven, which a woman took and hid in three measures of meal until it had been all leavened.
And Jesus said to them, See and beware of the leaven of the Pharisees and Sadducees.
How do ye not understand that it was not concerning bread I said to you, Beware of the leaven of the Pharisees and Sadducees?
Then they comprehended that he did not speak of being beware of the leaven of bread, but of the doctrine of the Pharisees and Sadducees.
And he charged them, saying, Take heed, beware of the leaven of the Pharisees and of the leaven of Herod.
In those times, the myriads of the crowd being gathered together, so that they trod one on another, he began to say to his disciples first, Beware of the leaven of the Pharisees, which is hypocrisy;
It is like leaven, which a woman took and hid in three measures of meal until the whole was leavened.
Your boasting is not good. Do ye not know that a little leaven leavens the whole lump?
Purge out the old leaven, that ye may be a new lump, according as ye are unleavened. For also our passover, Christ, has been sacrificed;
so that let us celebrate the feast, not with old leaven, nor with leaven of malice and wickedness, but with unleavened bread of sincerity and truth.