Matthew 16:12
Then they understood that he had told them to be on their guard, not against the leaven of bread, but against the teaching of the Pharisees and Sadducees.
Matthew 26:26
While they were eating, Jesus took some bread, and, after saying the blessing, broke it and, as he gave it to his disciples, said: "Take it and eat it; this is my body."
John 6:52-57
Upon this the Jews began disputing with one another: "How is it possible for this man to give us his flesh to eat?"
1 Corinthians 5:6-8
Your boasting is unseemly. Do not you know that even a little leaven leavens all the dough?
Galatians 5:9
A little leaven leavens all the dough.
1 Thessalonians 1:6
And you yourselves began to follow, not only our example, but the Master's also; and, in spite of much suffering, you welcomed the Message with a joy inspired by the Holy Spirit,