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.

James 3:17

But the [true] wisdom, which is from [God] above, is first of all pure, then peace-loving, patient and easily persuaded. [It is] full of mercy and produces a crop of good deeds; [it is] impartial [or, unwavering] and sincere.

1 Corinthians 5:7-8

Get rid of the old yeast [i.e., of sin, and especially the unrepentant sinner], so that you can be a new batch of dough, without yeast in it [i.e., a godly church without unrepentant sinners in it] as [I know] you really are. For our Passover [Lamb], Christ, has already been sacrificed.

Matthew 16:6-12

Jesus said to them, "Pay attention and watch out for the leavening [effect] of the Pharisees and Sadducees."

Mark 8:15-21

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].

Luke 5:1

Now it happened while Jesus was standing on the shore of Lake Genneseret [i.e., Lake Galilee] that the crowd was pushing closer to Him to hear God's message.

Luke 5:15

But the news about what Jesus had done spread all the more widely, so that large crowds assembled to listen to Him and to be healed of their sicknesses.

Luke 6:17

Then He came down [from the mountain] with them and stood on a level place [where] a large crowd of His disciples and a large group of people had gathered to hear Him and be healed from their diseases.

Luke 11:44

"It is too bad for you! For you people are like obscure grave sites that people walk over without knowing it."

Luke 12:56

You hypocrites! You know how to interpret the appearance of the earth and the sky, but why do you not know how to interpret [events of] this present time?

Acts 21:20

And when they heard [all] this, they gave honor to God, then said to Paul, "Brother, you can see how many thousands of Jewish believers [in Christ] there are [everywhere] and all of them are eager to observe the [requirements of the] law of Moses.

1 Corinthians 15:3

For I passed on to you the [following] main principles that I received [i.e., by revelation]: Christ died for our sins, according to the Scriptures;

1 Peter 2:1

Therefore, you should put out of your lives all malice [i.e., bad attitudes], and all deceit and hypocrisy, and all envy and unwholesome talk.

Treasury of Scripture Knowledge

Summary

In the mean time, when there were gathered together an innumerable multitude of people, insomuch that they trode one upon another, he began to say unto his disciples first of all, Beware ye of the leaven of the Pharisees, which is hypocrisy.

Bible References

First

1 Corinthians 15:3
For I passed on to you the [following] main principles that I received [i.e., by revelation]: Christ died for our sins, according to the Scriptures;
James 3:17
But the [true] wisdom, which is from [God] above, is first of all pure, then peace-loving, patient and easily persuaded. [It is] full of mercy and produces a crop of good deeds; [it is] impartial [or, unwavering] and sincere.

Which

Luke 12:56
You hypocrites! You know how to interpret the appearance of the earth and the sky, but why do you not know how to interpret [events of] this present time?
Luke 11:44
"It is too bad for you! For you people are like obscure grave sites that people walk over without knowing it."
James 3:17
But the [true] wisdom, which is from [God] above, is first of all pure, then peace-loving, patient and easily persuaded. [It is] full of mercy and produces a crop of good deeds; [it is] impartial [or, unwavering] and sincere.
1 Peter 2:1
Therefore, you should put out of your lives all malice [i.e., bad attitudes], and all deceit and hypocrisy, and all envy and unwholesome talk.

General references

Matthew 23:1
Then Jesus spoke to the crowds and to His disciples,
Luke 14:25
Now large crowds were following Jesus and He turned [around] and said to them,
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].