David Mathis serves as senior teacher and executive editor at desiringGod.org; a pastor at Cities Church in Saint Paul, Minnesota; and an adjunct professor at Bethlehem College & Seminary in Minneapolis. He and his wife, Megan, have four children. He is the author of several books, including Habits of Grace: Enjoying Jesus through the Spiritual Disciplines. Jonathan Parnell (MDiv, Bethlehem College & Seminary) serves as the lead pastor of Cities Church in Minneapolis-Saint Paul, Minnesota. He and his wife, Melissa, have five children. John Piper is founder and lead teacher of desiringGod.org and chancellor of Bethlehem College & Seminary. He served for thirty-three years as a pastor at Bethlehem Baptist Church in Minneapolis, Minnesota, and is the author of more than fifty books, including Desiring God; Don’t Waste Your Life; and Providence.