Contradiction with Matthew 16:12
This verse mentions leaven in the context of the teachings of the Pharisees and Sadducees, implying a negative connotation, whereas Luke 13:21 uses leaven positively as a metaphor for the Kingdom of God.
Matthew 16:12: Then understood they how that he bade [them] not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.
Contradiction with 1 Corinthians 5:6-7
In these verses, leaven symbolizes sin and corruption that should be purged, contradicting Luke 13:21 where leaven is used in a positive context.
1 Corinthians 5:6-7: Your glorying [is] not good. Know ye not that a little leaven leaveneth the whole lump?
Contradiction with Galatians 5:9
This verse uses leaven to symbolize a small influence that corrupts entirely, unlike Luke 13:21, where leaven represents the positive and pervasive growth of God's kingdom.
Galatians 5:9: A little leaven leaveneth the whole lump.