Definition and Context
In biblical terms, "defiled bread" refers to bread that has been rendered ceremonially unclean or impure according to the laws and customs of ancient Israel. The concept of defilement in the Bible often pertains to ritual purity, which was a significant aspect of the Israelites' covenant relationship with God. Bread, as a staple food, held both physical and spiritual significance, and its defilement could symbolize a breach in holiness or obedience to God's commandments.

Old Testament References
The notion of defiled bread is primarily found in the Old Testament, where the laws concerning clean and unclean foods are detailed. In Leviticus 21:6, the priests are instructed to be holy and not profane the name of God, as they offer "the food of their God." This implies that the bread and other offerings must be kept pure. The defilement of bread could occur through contact with unclean substances or through being offered by those who were themselves unclean.

In Ezekiel 4:13, the prophet is instructed to eat defiled bread as a sign of the impending judgment on Israel: "Then the LORD said, 'This is how the Israelites will eat their defiled bread among the nations to which I will banish them.'" This prophetic act symbolized the spiritual and physical degradation that would accompany their exile.

New Testament Considerations
While the New Testament does not explicitly mention "defiled bread," the concept of ritual purity continues to be addressed, particularly in the context of Jesus' teachings. In Mark 7:18-19, Jesus challenges the Pharisaic emphasis on external purity, stating, "Are you still so dull? Do you not see that nothing that enters a man from the outside can defile him, because it does not enter his heart but his stomach, and then it is eliminated?" This teaching shifts the focus from external ritual purity to the purity of the heart.

Theological Implications
The idea of defiled bread serves as a metaphor for spiritual impurity and the consequences of disobedience to God's laws. In the Old Testament, the defilement of bread often symbolized Israel's unfaithfulness and the resulting separation from God. The prophetic use of defiled bread in Ezekiel underscores the seriousness of covenantal breaches and the reality of divine judgment.

In the New Testament, the emphasis on internal purity over external ritual observance reflects the transformative nature of the New Covenant, where the heart's condition takes precedence over ceremonial law. This shift highlights the fulfillment of the law through Christ and the call for believers to pursue holiness from within.

Cultural and Historical Context
In ancient Israel, bread was not only a dietary staple but also a significant element in religious rituals, such as the showbread placed in the Tabernacle (Exodus 25:30). The defilement of bread, therefore, had both practical and symbolic ramifications, affecting daily life and worship practices. Understanding the cultural and historical context of defiled bread provides insight into the broader biblical themes of purity, holiness, and the relationship between God and His people.