"No grain offering which you bring to the LORD shall be made with leaven, for you shall burn no leaven nor any honey in any offering to the LORD made by fire.
Then Jesus said to them, "Take heed and beware of the leaven of the Pharisees and the Sadducees."
1 Corinthians 5:6-8
Your glorying is not good. Do you not know that a little leaven leavens the whole lump? Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover, was sacrificed for us. Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.
1 John 4:20-21
If someone says, "I love God," and hates his brother, he is a liar; for he who does not love his brother whom he has seen, how can he love God whom he has not seen? And this commandment we have from Him: that he who loves God must love his brother also.
"When anyone offers a grain offering to the LORD, his offering shall be of fine flour. And he shall pour oil on it, and put frankincense on it. He shall bring it to Aaron's sons, the priests, one of whom shall take from it his handful of fine flour and oil with all the frankincense. And the priest shall burn it as a memorial on the altar, an offering made by fire, a sweet aroma to the LORD
"Teacher, which is the great commandment in the law?" Jesus said to him, "'You shall love the LORD your God with all your heart, with all your soul, and with all your mind.' This is the first and great commandment. And the second is like it: 'You shall love your neighbor as yourself.'
Then He charged them, saying, 'Take heed, beware of the leaven of the Pharisees and the leaven of Herod.'
In the meantime, when an innumerable multitude of people had gathered together, so that they trampled one another, He began to say to His disciples first of all, "Beware of the leaven of the Pharisees, which is hypocrisy.
And God said, "See, I have given you every herb that yields seed which is on the face of all the earth, and every tree whose fruit yields seed; to you it shall be for food.
But you shall not eat flesh with its life, that is, its blood.
Then the priest shall take from the grain offering a memorial portion, and burn it on the altar. It is an offering made by fire, a sweet aroma to the LORD.
Another parable He spoke to them: "The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened."
How is it you do not understand that I did not speak to you concerning bread?—but to beware of the leaven of the Pharisees and Sadducees."
And we know that all things work together for good to those who love God, to those who are the called according to His purpose.
A little leaven leavens the whole lump.
Love has been perfected among us in this: that we may have boldness in the day of judgment; because as He is, so are we in this world.