The Lord (YHVH) commanded the grain offering on Shavuot, (known as Pentecost among Christians), to be made of the finest flour, baked with yeast, that is, leaven. Leaven, in the Bible, is almost universally, a symbol for "sin", and in the OT is strictly forbidden on the altar of YHVH., yet here, in the Feast of Weeks it is commanded as part of the offering. Just six weeks prior to this festival, Israel had spent a week eating unleavened bread, a clear picture of the connection between the Passover Lamb and the removal of sin from our lives. Now the grain offering for Shavuot contains yeast; two loaves with it. Why? A common interpretation of this for NT believers is that the loaves represent Jews and Gentiles, the two types of redeemed people, who, of course, still contain sin in our lives.
So the sequence of these two spring festivals can be seen to illustrate, on the one hand, our perfect deliverance from sin and death through the Passover Lamb (Yeshua); and subsequently, the reality of our true condition as "leavened loaves" offered to the Lord as "first-fruits". We know that having come to faith in Yeshua (Jesus), cleansed by His shed blood, we stand righteous and perfect in Him; and yet, we constantly struggle with our Adamic nature. In this light, Shavuot begins to emerge as a festival marking and illustrating the opportunity and means for our transformation. The Lord's sending forth of His Holy Spirit at this time awakens and empowers us to change; to be inwardly transformed from the old creation into a new creation.
On the day of Pentecost, 2000 years ago, this transformation process was dynamically accelerated and made accessible to every believer. Baptized with the Holy Spirit of God, and with His fire, our sinful nature with all its impurities and "leaven" takes a back seat to the powerful indwelling of the Spirit of Messiah, so that as we continually pray, walk in obedience, and thus cooperate to be filled with His Spirit, we are sanctified and transformed into His likeness - "from glory to glory", and so become His effective witnesses. Praise God that He works with our issues-- and is transforming us into a bride without wrinkle or spot!
Allow the Holy Spirit to burn away the impurity of your sinful nature; to purge out the dross, and deeply penetrate your life. The process can be "firey" and involve some painful sacrifices, but the result is purity and the holiness without which no one will see God. And remember that Yeshua is returning soon, greatly anticipating a bride who is prepared for His arrival! (George, Baht Rivka, Elianna & Obadiah)