Israel's worship in the Old Testament is the liturgical heritage of all Christian worshipers. John Schuurman and Jane Tiemersma Vogel write in Reformed Worship that celebrating Old Testament festivals in their worship helped worshipers "understand the context of God's mighty acts," deepened their awareness of "a big part of our Bibles of which we were previously unaware," focused them on "ways of keeping covenant with younger generations," and, above all, helped worshipers to "worship and bring glory to God."
Consider deepening your worshiping community's knowledge of its Hebrew heritage, and expanding its worship, by celebrating Old Testament festivals—keeping a constant eye on the fulfillment of God's promises to Israel in the coming of Jesus Christ.
Worship Resources
Sound the Trumpet: Celebrating the Old Testament Fall Festivals (Reformed Worship)
John Schuurman and Jane Tiemersma Vogel
Jewish Festivals and the Christian Faith (Restoration Foundation)
A Christian Observes Yom Kippur (www.religion-online.org)
Harvey Cox
Celebrating the Old Testament Feasts in Christian Worship
Worship Renewal Grant Project by Monroe Community Church
Biblical Resources
Biblical Holidays: Returning to a Biblical Foundation (www.biblicalholidays.com)
Robin Sampson
Other Resources
Restoration Foundation
A Gentile's Guide to the Jewish Holidays from Judaism 101
Jewish Holidays from Wikipedia