Why did ancient Israel observe the Feast of Unleavened Bread?

"... For seven days eat unleavened bread, the bread of affliction, because you left Egypt in haste—so that all the days of your life you may remember the time of your departure from Egypt" (Deuteronomy 16:3, NIV).

"Eat unleavened bread during those seven days; nothing with yeast in it is to be seen among you, nor shall any yeast be seen anywhere within your borders. On that day tell your son, 'I do this because of what the LORD did for me when I came out of Egypt'" (Exodus 13:7-8, NIV).
What instruction did Paul give Christians in regard to this festival?

"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" (1 Corinthians 5:8).

Paul did not treat these festivals as outdated Jewish traditions. He considered them essential observances for God's called and chosen people in all ages and cultures. He understood their relationship to Christ's role in God's master plan.

Paul commanded the Corinthian Christians—mostly gentiles (non-Israelites)—to keep the Feast of Unleavened Bread. His instructions show that Christians from non-Jewish communities and cultures kept the Days of Unleavened Bread. Setting an example for all Christians today, these Jews and non-Jews observed these days in accordance with God's laws.

The Feast of Unleavened Bread, the second of God's annual festivals, represents the second step in God's plan for our redemption. Its main focus is on Christ as our Deliverer, our Savior. Therefore it is a thoroughly Christian festival.

That is why Paul compares a Christian's deliverance from sin through the sacrifice and assistance of Christ to Israel's deliverance from the Egyptian army at the Red Sea (which probably occurred on the final day of the Feast of Unleavened Bread). He writes: "Moreover, brethren, I do not want you to be unaware that all our fathers [ancient Israel] were under the cloud, all passed through the sea, all were baptized into Moses in the cloud and in the sea, all ate the same spiritual food, and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ" (1 Corinthians 10:1-4).

After we are justified by Christ's sacrifice at the time of baptism, we must be led out of sin and into a righteous pattern of life just as Israel was led out of its bondage during the same Days of Unleavened Bread. This festival represents the work of the living, resurrected Christ directly leading and assisting us in overcoming sin.

Paul explained: "Much more then, having now been justified by His blood, we shall be saved from wrath through Him. For if when we were enemies we were reconciled to God through the death of His Son, much more, having been reconciled, we shall be saved by His life" (Romans 5:9-10).

Paul later expressed the same basic thought in different words: "I can do all things through Christ who strengthens me" (Philippians 4:13). He also explained: "... God has chosen to make known among the Gentiles the glorious riches of this mystery, which is Christ in you, the hope of glory. We proclaim him, admonishing and teaching everyone with all wisdom, so that we may present everyone perfect in Christ. To this end I labor, struggling with all his energy, which so powerfully works in me" (Colossians 1:27-29, NIV).

Did Paul explain the spiritual lesson behind our observance of the Feast of Unleavened Bread?

"Do you not know that a little leaven leavens the whole lump? Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover, was sacrificed for us" (1 Corinthians 5:6-7).

One purpose for the Feast of Unleavened Bread is to remind us that, after we accept Christ's sacrifice at the time of baptism, we must allow God's Spirit to help us grow up into Christ spiritually (Ephesians 4:15; compare Galatians 2:20). Leavened bread represents the wrong motives (malice) and sin (wickedness) that may still reside in our thinking. Unleavened bread represents having our hearts filled with sincere motives—an eagerness to apply the pure truth revealed in God's Word.

Jesus earlier made the same point to His disciples. He told them, "Beware of the leaven of the Pharisees, which is hypocrisy" (Luke 12:1). He also compared leaven to the false doctrines taught by many of the religious leaders of the day (Matthew 16:6-12). They, like many false teachers today, substituted their own ideas and traditions for God's commandments (Matthew 15:3-9).

Those who accept Christ as their Passover—as the New Covenant Lamb of God—have their sins covered by His sacrifice, providing they sincerely repent of their wickedness and malicious motives so they can begin conforming their lives to the truth as it is revealed in God's Word.

Therefore, just as God delivered ancient Israel from literal slavery, God's second step in His plan of salvation is freeing repentant Christians from spiritual slavery to wickedness (Romans 6:17-19).

The Feast of Unleavened Bread celebrates Christians being miraculously delivered from this spiritual bondage of sin just as surely as God delivered the ancient Israelites from their Egyptian bondage. It reminds us that our deliverance from sin and our salvation are available only through a personal relationship with Christ, the "Lamb of God" who took on Himself the penalty for our sins (1 Thessalonians 5:9-10; John 1:36). As our High Priest, He actively helps us, if we really are His servants, to put the leaven of sin out of our lives so we may become spiritually unleavened (Hebrews 3:1; Hebrews 10:19-23; 1 Corinthians 5:7).

The Feast of Unleavened Bread celebrates Jesus' role in helping us remove spiritual leaven including malice, wickedness and hypocrisy from our character and in replacing those evil qualities with godly obedience, love and truth.

Therefore, "seeing then that we have a great High Priest who has passed through the heavens, Jesus the Son of God, let us hold fast our confession. For we do not have a High Priest who cannot sympathize with our weaknesses, but was in all points tempted as we are, yet without sin. Let us therefore come boldly to the throne of grace, that we may obtain mercy and find grace to help in time of need" (Hebrews 4:14-16). He leads and assists us in resisting even the temptations of sin.

Christ is actively perfecting God's own nature in His servants (Matthew 5:48; 2 Peter 1:4). That is why Paul told Christians, "Therefore let us keep the feast [of Unleavened Bread] ..." (1 Corinthians 5:8).