God initiated seven annual festivals and sabbaths in the Old Testament. These days represent steps in God's plan to save mankind through Jesus Christ. Ancient Israel never understood the meaning of those days, but God's Church is able to keep those days with understanding of their true meaning as ancient Israel was not able to do. Yet most of traditional Christianity has rejected God's holy days and feast days that are given in the Bible in favor of days based on the traditions of men, such as Christmas and Easter, with the fertility symbols of the evergreen tree, rabbits, and eggs so common among pagan religions in ancient times. You can look up those symbols and rituals in any encyclopedia to see where they come from. And God clearly tells us not to worship Him imitating the way pagans worship their gods, but to worship God exactly the way He tells us to worship Him (Deuteronomy 12:29-32).
In rejecting God's ordained annual festivals in favor of man-made religious festivals, man is following the same pattern of choosing the traditions of men as he has followed in substituting Sunday for God's seventh-day Sabbath.
Some ministers teach that to keep the annual holy days of God is to deny the sacrifice of Jesus Christ. Is this true?
We can look to the New Testament Church of God to see what they practiced. Did the first century Church of God keep these festivals?
The New Testament Church of God kept the Feast of Unleavened Bread. Was it only the Jewish Christians who kept this feast? No. Paul was apostle to the gentiles, and he taught the Church of God at Corinth to keep the Feast of Unleavened Bread.
The description of this festival is in the Old Testament. Notice: "On the fourteenth day of the first month at twilight is the Lord's Passover. 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. On the first day you shall have a holy convocation; you shall do no customary work on it. But you shall offer an offering made by fire to the Lord for seven days. The seventh day shall be a holy convocation; you shall do no customary work on it" (Leviticus 23:5-8). Now notice how Paul likens leavening to sin in 1 Corinthians 5:1-8, and he compares unleavened bread to sincerity and truth. Notice especially verses 6-8. After talking about the sin of sexual immorality in that congregation, he says, "Your glorying is not good. 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. 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." This helps us understand the meaning and lesson of this feast, that is, we put leavening out of our houses for seven days and this represents the lesson that we are to put sin out of our lives, or in other words, the lesson of repentance (Acts 2:38).
Notice especially Paul's statement, "let us keep the feast" (1 Corinthians 5:8). This shows that Paul instructed and commanded the Corinthians to keep the Feast of Unleavened Bread, one of the seven annual feasts of God, for there is no other feast that would fit this context.
Does keeping God's annual feast days invalidate or deny the sacrifice of Christ? No, because Paul would not have instructed the Corinthians to keep the feast if that were the case.
However, since the Levitical priesthood has been replaced by the priesthood of Jesus Christ, there is no Levitical priesthood to offer animal sacrifices, so those are omitted.
For more information on this festival, see The Days of Unleavened Bread - Repentance.
For those who might be interested in observing this festival, but don't know the dates, the Days of Unleavened Bread in 2009 are seven days starting Thursday, April 9 through Wednesday, April 15. The first and last days are Sabbath days of rest. God counts days from sunset to sunset, so from sunset Wednesday, April 8 till sunset Thursday, April 9 I will observe a sabbath rest and likewise from sunset Tuesday, April 14 till sunset Wednesday, April 15. During the entire seven day festival I will refrain from eating any products with leavening in them (yeast, baking soda, baking powder), and I will make sure I do not have leavening or products with leavening in my house or personal space if I am living in someone else's house. I will also eat some kind of unleavened bread each of those seven days, such as matzos.
Taking the time to clean my space before these days start and making sure I get rid of any leavened products reminds me each year of my personal responsibility to examine my life and get rid of sin wherever I find it. Being careful to not forget and accidentally eat leavened products like donuts at work or anyplace during this time reminds me of the lesson that I have to be diligent to not sin by breaking God's commandments in the letter or spirit. Eating unleavened bread each day reminds me of my need to seek the righteousness that is from God and to seek God diligently each day in prayer and Bible study.