God instituted the seven-day Feast of Unleavened Bread, which immediately follows the Passover (Leviticus 23:6-8 Leviticus 23:6-8  And on the fifteenth day of the same month is the feast of unleavened bread to the LORD: seven days you must eat unleavened bread.
 In the first day you shall have an holy convocation: you shall do no servile work therein.
 But you shall offer an offering made by fire to the LORD seven days: in the seventh day is an holy convocation: you shall do no servile work therein.
American King James Version×). Historically it commemorated the ancient Israelites fleeing from slavery in Egypt in such haste that they didn’t have time to leaven their bread or let it rise (Exodus 12:33-34 Exodus 12:33-34  And the Egyptians were urgent on the people, that they might send them out of the land in haste; for they said, We be all dead men.  And the people took their dough before it was leavened, their kneading troughs being bound up in their clothes on their shoulders.
American King James Version×).
God commanded the Israelites to keep this festival by removing leaven (such as yeast) out of their homes for seven days and to avoid eating any leavened foods during this time. The first and last days of this weeklong festival are set apart as holy convocations—annual Sabbaths—days devoted to rest and meeting together to be taught and to worship God.
Jesus identified leaven as a symbol of sin (Matthew 16:6-12 Matthew 16:6-12  Then Jesus said to them, Take heed and beware of the leaven of the Pharisees and of the Sadducees.
 And they reasoned among themselves, saying, It is because we have taken no bread.
 Which when Jesus perceived, he said to them, O you of little faith, why reason you among yourselves, because you have brought no bread?
 Do you not yet understand, neither remember the five loaves of the five thousand, and how many baskets you took up?
 Neither the seven loaves of the four thousand, and how many baskets you took up?
 How is it that you do not understand that I spoke it not to you concerning bread, that you should beware of the leaven of the Pharisees and of the Sadducees?
 Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.
American King James Version×; Mark 8:15 Mark 8:15And he charged them, saying, Take heed, beware of the leaven of the Pharisees, and of the leaven of Herod.
American King James Version×; Luke 12:1 Luke 12:1In the mean time, when there were gathered together an innumerable multitude of people, so that they stepped one on another, he began to say to his disciples first of all, Beware you of the leaven of the Pharisees, which is hypocrisy.
American King James Version×). Members of the Church started by Christ continued to celebrate this festival by putting leaven out of their homes for the week as a symbol of the sinless lives and attitudes God desires of His people. Paul, the apostle to the gentiles, even commanded the Church members in Corinth, “Let us keepthe 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 1 Corinthians 5:8Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
American King James Version×).
After accepting Christ’s sacrifice for our sins, we must follow His example in living a life of righteousness, striving to keep sin out of our life.
It was during the Feast of Unleavened Bread that Jesus was raised from the dead—a vital factor for us to be delivered out of sin and on the path to God’s Kingdom. Christians who celebrate this festival see that its meaning leads directly to the meaning of the third festival of God, the Feast of Pentecost.