Matthew 16:6
Jesus said to them, "Pay attention and watch out for the leavening [effect] of the Pharisees and Sadducees."
Luke 12:1
About this time, while a crowd of many thousands had assembled, [so large that] people were trampling on one another, Jesus first began telling His disciples, "Watch out for the leavening [effect] of the Pharisees, which is hypocrisy.
Mark 8:15
Then Jesus ordered them, saying, "Pay attention and watch out for the leavening [effect] of the Pharisees and Herod." [Note: By "Herod" is probably meant the Herodians, who were a party favorable to King Herod and, along with the Pharisees and Sadducees, were out to get Jesus. See Matt. 16:6].
1 Corinthians 5:6-8
Your boasting is not good. Do you not know that a little yeast can leaven the whole batch of dough?
Galatians 5:9
A little bit of yeast permeates the whole batch of dough [i.e., a few people can influence everyone else to do the wrong thing in this matter].
Matthew 16:12
Then they understood that He was not telling them to watch out for the yeast in [physical] bread, but for the teaching of the Pharisees and Sadducees.
Luke 12:15
And [then] He said to them, "Be careful and guard yourselves against [practicing] all forms of greed, for a person's life does not consist of having a lot of possessions."
2 Timothy 2:16-17
But avoid worldly, empty chatter, for those who practice it will become more and more ungodly,