Matthew 16:6 contains the direct warning 'beware of the leaven of the Pharisees and Sadducees' — the very saying that verse 12 then explains is about their teaching.

Matthew 15:4 shows the Pharisees' teaching (tradition) contradicting God's command — an example of the corrupt leaven Jesus warns against in 16:12.

In Matthew 23, Jesus pronounces woes against Pharisees and scribes, exposing their hypocrisy and false teaching — the very leaven warned about in the main verse.

In Matthew 3:7, John the Baptist calls the Pharisees and Sadducees a 'brood of vipers,' rebuking them — this parallels Jesus' later warning against their teaching.

Matthew 22:16 shows Pharisees sending disciples with Herodians to trap Jesus — an example of their deceptive teaching and hypocrisy, the leaven warned against.

Mark 8:15 records the same warning: 'beware of the leaven of the Pharisees and the leaven of Herod' — a direct parallel account to Matthew 16:6 and its explanation.

Acts 23:8 explains the doctrinal differences between Pharisees and Sadducees (resurrection, angels, spirit) — providing background for why both groups' teaching is dangerous.

Exodus 12:15 commands removing leaven from homes during Passover — a symbol of purging corruption, paralleling the warning against corrupt teaching in the main verse.

Leviticus 2:11 forbids leaven in grain offerings because leaven symbolizes sin — same symbolic use as the corrupt teaching Jesus warns against in the main verse.

1 Corinthians 5:8 uses leaven as a metaphor for moral corruption — a parallel image to Jesus using leaven for false teaching.