Answer
In the lives of Old Testament believers, the various festivals, the Sabbath observances, sacrificial offerings that were made, they played a very important role. First of all, they were to remind Israel that its life as the people of God was a gift to them. For instance, the Passover was meant to remind them that they were once slaves in Egypt, and God and God alone has set them free. But not just to remind them that they were set free, because they were set free from Egypt to be taken to Sinai where God would establish his covenant with them. So the festival life of Israel was meant to be a reminder to them that God and God alone has called them to be his people, to remember the mighty works of God to save them. The Sabbaths were meant to remind them of two things, that the world is Yahweh's and that they didn't create themselves, and they didn't free themselves from slavery. In Exodus, Moses says, "Keep the Sabbath, for on the Sabbath day God rests." In the book of Deuteronomy, Moses says keep the Sabbath because not only did God rest on the Sabbath day, but remember that you were once slaves in Egypt. All of the festivals were meant to remind them of what God has done to redeem them and to remind them that they are alone the people of God because of God's gracious goodness toward them, and out of those practices have their lives shaped, their self-understanding shaped, so that they would begin and continue to respond faithfully to God in lives of obedience, trust, love and service.
Answer by Dr. Steve Blakemore
Dr. Steve Blakemore is the Assistant Professor of Philosophy at Wesley Biblical Seminary