Paul uses the metaphor of yeast and unleavened bread to illustrate the need for purity and holiness in the Christian community. In Jewish tradition, yeast is often associated with sin and corruption, as even a small amount can permeate an entire batch of dough. By urging the removal of the old yeast, Paul is calling for the elimination of sinful behaviors and attitudes that can corrupt the community. This cleansing is essential for believers to become a new, pure batch of dough, reflecting their true nature in Christ.
The reference to Christ as the Passover lamb highlights the sacrificial aspect of Jesus' death, which brings about redemption and liberation from sin, similar to how the Passover lamb's sacrifice led to the Israelites' liberation from Egypt. This imagery reinforces the idea that through Christ's sacrifice, believers are made new and are called to live in a way that reflects this transformation. The call to holiness is not just about individual purity but also about maintaining the integrity and unity of the Christian community, living in sincerity and truth.