"Besides the cakes, he shall offer for his offering leavened bread with the sacrifice of thanksgiving of his peace offerings." Leviticus 7:13
Leaven was never added to the offerings of God, but in this verse, it is commanded. In the law of the peace offering given in the previous verse, unleavened bread was commanded.
"If he offer it for a thanksgiving, then he shall offer with the sacrifice of thanksgiving unleavened cakes mingled with oil, and unleavened wafers anointed with oil, and cakes mingled with oil, of fine flour, fried." Leviticus 7:12
The question is, why the different laws for the same offering? Peace with God is what the believer shares with God having been forgiven of his sins. When he presents his peace offering, which is a thanksgiving offering, it has to first represent the sinless perfection of God who has graciously brought him into fellowship with Himself through the efficacious sacrifice of His Son. This is fully met in the first aspect of the peace offering that the believer brings without leaven.
But in the second aspect of his peace offering, he adds leaven to his offering. This represents the believer whose imperfection is indicated by the presence of leaven. It is true that the believer has been saved by the perfect sacrifice of Jesus Christ, yet, this perfect sacrifice did not make the believer a perfect person, there is still evil in him, which leaven represents. Through the work of the Holy Spirit in the believer's life, this presence of evil is progressively minimized, but not eradicated. When Christ returns, then, everything occasioned by sin will be eradicated.
Toni
