In Matthew 16:6-12, Jesus warns against the 'leaven of the Pharisees' — their teaching — using the same metaphor of leaven corrupting the whole lump.

In Mark 8:15, Jesus warns of the leaven of the Pharisees and Herod — a parallel warning about corrupting influence spreading.

In Luke 12:1, Jesus says 'Beware of the leaven of the Pharisees, which is hypocrisy' — same metaphor for corrupting teaching.

In Luke 13:21, leaven represents the kingdom of God spreading positively — a contrasting use to Paul's warning about corrupting influence.

In 1 Corinthians 5:6, Paul uses the exact same proverb about a little leaven leavening the whole lump, now about church discipline.

In 1 Corinthians 5:7, Paul expands the leaven metaphor to 'cleanse out the old leaven' with Passover imagery — same author, same metaphor.

In Matthew 13:33, leaven symbolizes the kingdom's growth — opposite of Paul's warning here about corrupting influence. Same image, contrasting uses.

In Exodus 12:8, unleavened bread is commanded for Passover — leaven symbolizes sin and corruption, the OT background for Paul's metaphor.

In Leviticus 2:11, leaven is forbidden in grain offerings — reinforcing leaven as impurity, the OT basis for the metaphor.