In the Parable of the Leaven, as recorded in Matthew 13:33 and Luke 13:20-21, Jesus Christ forewarns of internal doctrinal distortions that would affect God's church through the centuries until His second coming. This parable, one of the first four in Matthew 13, reveals the future progress of the church, specifically how God's doctrines are corrupted. Leaven in this parable represents evil and corruption. Physically, it is a substance that causes dough to rise, often symbolizing a process of decay or fermentation. Jesus Christ uses leaven to signify the evil doctrines of groups like the Pharisees, Sadducees, and Herod, pointing to corruptions such as hypocritical formality, skepticism, and self-indulgence in worldly desires. The leaven is hidden in the meal, illustrating how satan subtly strikes against the truth, spreading disintegration and corruption within the church. Its diffusive quality highlights the harmful effects of false doctrine, acting as a persuasive force that hinders obedience to the truth. The woman in the parable represents a system of beliefs and practices that influence others, often contrary to God. She surreptitiously hides the leaven of false doctrine in the meal, encrypting or concealing it within the church. Her actions depict an opponent of Christ, infusing His church with corrupting ideas that undermine the truth. The three measures of meal symbolize love, service, and loyalty to others, particularly within the church. This large quantity, recognized by many Jews as akin to a grain offering that must remain unleavened, represents the offerer's dedication to fellow human beings. Jesus Christ warns that false doctrines, stealthily introduced, would erode these relationships, fostering insensitive, uncaring, and self-centered attitudes that spread through the church like leaven in dough, until all is leavened.

The unique offering on the Feast of Weeks (Pentecost) serves as a parable that teaches about the Messiah. The two loaves baked with leaven form the centerpiece of this offering, raising a serious question due to leaven's universal representation of corruption in Scripture, yet here it appears in a holy day offering. This introduces a tension that must be resolved to understand the offering. The mystery deepens with the presence of not one, but two leavened loaves, suggesting a difference, as the number two signifies that there is another. This difference may not be benign, as the priest bakes the two wave loaves with leaven, symbolically indicating corruption. Differences with carnality often produce division, if not enmity. This picture poses the question of how God could accept an offering of loaves characterized by carnality.

Leaven, as a symbol of sin and corruption, holds significant meaning in the observance of the Feast of Unleavened Bread. Throughout the New Testament, God uses leaven to represent sin, with Jesus warning against the leaven of the Pharisees, which is hypocrisy. Paul also emphasizes the danger of sin spreading by stating that a little leaven leavens the whole lump. He instructs that the purpose of keeping the Feast of Unleavened Bread is to remind us of our need to remove sin from our lives. When deleavening our homes, we symbolize purging sin from our lives, though cleansing ourselves of sin is a lifetime process that will not be completely fulfilled until we are transformed into spirit. As long as we remain flesh and blood, we will never be absolutely perfect or free ourselves completely of sin. This constant struggle to overcome human nature and put on God's nature is a vital part of our journey. God desires us to observe the Feast of Unleavened Bread annually to remind us that we are not perfect and that our lives involve a constant battle against sin. When we deleaven our homes, we often find that, no matter how hard we try, we cannot locate every tiny crumb, illustrating how deceitful sin is and teaching us to constantly examine ourselves to purge it from our lives. Removing sin is hard work, and the Days of Unleavened Bread serve as an annual reminder of this ongoing warfare that all Christians must wage throughout their lives. The object lesson of deleavening our homes retains great meaning and purpose, as the symbolism of putting sin out of our lives will not be fully realized until we are changed and inherit the Kingdom of God, becoming like Him who cannot sin.

The Pentecost grain offering contains leavening, unlike the typical grain offering, and because of this, God forbids the priest from placing the loaves on the altar. As stated in Leviticus 2:11-12, no grain offering brought to the LORD shall be made with leaven, for no leaven or honey shall be burned in any offering to the LORD made by fire. The leavened loaves of the firstfruits on Pentecost are offered to the LORD, but they are not burned on the altar for a sweet aroma. The altar represents God's table, and He never partakes of corruption. Instead of burning, the priest waves the loaves before God, symbolizing His close inspection and hopeful acceptance, though He designates them for the priest's use rather than as His portion. Scripture consistently portrays leavening as a symbol of corruption. If leavening represented something positive in the Pentecost offering, it would be acceptable on God's altar, but He clearly distances Himself from it. Even the symbolism of oil, poured on the grain offering and representing wealth, abundance, health, energy, and God's gifts, cannot fully counteract the corrupting effect of leaven. As long as we remain in this flesh, a taint of corruption persists, and the symbol of leavening in the wave loaves relates to this life rather than the resurrection, where the corruptible will put on incorruption. In the ritual sequence, the priest does not wave the leavened loaves alone, as there would be no basis for God's acceptance. According to Leviticus 23:20, the priest waves them with the bread of the firstfruits and with two lambs of the peace offering as a wave offering before the LORD. Portions of the burnt and sin offerings are also waved alongside the loaves and lambs. God's acceptance of the leavened loaves, representing a harvest of devotion and service tainted by differences and carnality, depends on their association with the substantial burnt offering, the peace offering, and especially the sin offering. Only then does God accept the leavened offering, though He does not allow it on His altar, reserving it for the priest's use while His portion remains without leaven.