Why was the bread offered at Pentecost to be made with leaven?
Question:
"You shall bring from your dwellings two wave loaves of two-tenths of an ephah. They shall be of fine flour; they shall be baked with leaven. They are the firstfruits to the LORD" (Leviticus 23:17 NKJV)
Answer:
Just because a leaven is used to represent sin in some of Paul's illustrations, it doesn't mean that every use of leaven is done to represent sin.
The Passover meal occurred during the Feast of Unleavened Bread. The lack of leavening was to commemorate the rush Israel had in leaving Egypt. They couldn't use leavening because waiting for bread to rise would have taken too long. "You shall sacrifice the Passover to the LORD your God from the flock and the herd, in the place where the LORD chooses to establish His name. You shall not eat leavened bread with it; seven days you shall eat with it unleavened bread, the bread of affliction (for you came out of the land of Egypt in haste), so that you may remember all the days of your life the day when you came out of the land of Egypt. For seven days no leaven shall be seen with you in all your territory, and none of the flesh which you sacrifice on the evening of the first day shall remain overnight until morning" (Deuteronomy 16:2-4).
The Feast of Pentecost was to celebrate the first harvest. This is a remembrance of how God brought them into a bountiful land, which was celebrated with food from the home. "You shall bring in from your dwelling places two loaves of bread for a wave offering, made of two-tenths of an ephah; they shall be of a fine flour, baked with leaven as first fruits to the LORD" (Leviticus 23:17). Thus, it is a celebration of thankfulness for what the Lord provided them. Bread is used because the Feast of Pentecost comes at the beginning of the wheat harvest (Exodus 34:22).
Thus, Passover reminded the Israelites of the hardships endured to travel to freedom, and Pentecost is to remind them of the blessings they received on arriving in the promised land.