Seven times, God says to eat unleavened bread for seven days. He is very clear.
It is commonly held that Unleavened Bread is about putting sin out of our lives. And while that is an aspect, if we were to go through all of God's instructions for Unleavened Bread, we would see that His reason and emphasis are different. What God overwhelmingly emphasizes is His deliverance, not our work of avoiding leavening and thus sin (Exodus 12:17; Exodus 13:3, 8-9; 23:15; 34:18; Deuteronomy 16:3).
The overarching reason for that feast, and the reason we eat unleavened bread for seven days, is to remember God's deliverance. When we get to the New Testament, Jesus identifies Himself as the bread of God - the bread of life. He was entirely unleavened.
Further, Paul tells us in I Corinthians 5:8, Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth. Christ is the embodiment of sincerity and truth. He is the One who delivered us from this present, evil age, from spiritual bondage, from the power of darkness. And it is through the strength that He supplies that we have the means to overcome sin. And that strength comes from ingesting His word and beseeching Him to live His life in us every day.
The unleavened bread that God says we must eat for seven days represents Christ Himself. To miss eating the unleavened bread of sincerity and truth is to miss out on the divine connection with our Savior. Our minds should rebel at the thought of skipping that.
It is similar with Passover. The bread and wine are the symbols of Passover. It wouldn't be Passover without them. These things may just be symbols, but these symbols signal to God our intent and our desire to fulfill all righteousness, even in the symbols.
In the same way, we keep the Feast of Unleavened Bread for seven days by eating unleavened bread each day and not merely avoiding leavening. Consider what neglecting to eat the unleavened bread of life every day would signal to God. The symbols matter.
Faithful and righteous Daniel chose to spend the night in a cave of lions rather than give up his bread of life for a single day. That's how important his connection with God, and being strengthened by God, was to Daniel. It is those who know their God who will be strong and carry out great exploits, but that strength and knowledge of God come from continually partaking of what, or of Whom the unleavened bread represents.
We can apply that to the lessons of Unleavened Bread. God says repeatedly that the reason we keep that feast and eat unleavened bread is because of what He did. He delivered Israel from Egypt and the power of the Pharaoh. Likewise, He delivered us from this present evil age and its adversarial ruler. He delivered us from spiritual Egypt and has given us a new home.
The Israelites only had physical houses, but we have a spiritual house that can give us far greater stability, if we allow it. Now, we could go to Matthew 7 and plug in the parable of the two builders and apply the houses there to our lives, and that does fit. But there is another way to apply the house symbolism, which we will see in Hebrews 3, if you would turn there:
As with so many things, the symbol of the house points us back to Christ as well. He has built and is building a spiritual house, and we are that house, as long as we hold fast the confidence and the rejoicing of the hope firm to the end. We are that house because we are in Him. Jesus promised that the gates of the grave would not prevail against the church - this house. The individual members die physically, but this house has continued for some 2,000 years. It has a sure foundation.
This does not mean that this house is always tranquil inside, because it consists of still-imperfect people, and the carnality that remains tends to cause friction. But in the long view, the house is far more stable than anything that spiritual Egypt … . . .
In verse 17, God gives the fundamental reason for this feast. It says, “for on this same day I will have brought your armies out of the land of Egypt.” In other words, it is a memorial of God’s deliverance. That’s why God commands this Feast to be observed—to continually remember His deliverance. That’s the foundation. All the other aspects of this Feast build on top of it. The eating of unleavened bread and avoiding leavening are things we do in response, but the reason God gives for the feast is to memorialize His deliverance.
These verses contain something else. Even though rejoicing is not directly mentioned in the instructions, it is still a feast, and so rejoicing is implied. Granted, the food we eat is somewhat unusual compared to what we normally associate with a festive occasion. We have to rejoice without pretzels or pizza or cookies. Instead, our rejoicing includes the bread of affliction, which we will look at later. But nevertheless, this feast is an appointed time for us to remember God’s deliverance, and rejoicing should be the result.
This is a sidenote, but it relates here. We commonly refer to this week as the “Days of Unleavened Bread.” That phrase is only used in two places, both in Acts (Acts 12:3; 20:6). It refers to the time or season in which unleavened bread is used, and that span of time began before the seven-day Feast. But the Bible consistently calls the seven-day observance itself the “Feast of Unleavened Bread,” which shows that it is a time to celebrate. Physical Israel kept this Feast as a memorial of God’s deliverance from Egypt. Spiritual Israel keeps this Feast as a memorial of an even greater, spiritual deliverance.