Thabiti M. Anyabwile (MS, North Carolina State University) serves as a pastor at Anacostia River Church in Washington, DC, and is the author of numerous books. He serves as a council member of the Gospel Coalition, is a lead writer for 9Marks Ministries, and regularly blogs at The Front Porch and Pure Church. He and his wife, Kristie, have three children. John Piper (DTheol, University of Munich) is the founder and teacher of desiringGod.org and the chancellor of Bethlehem College & Seminary. He served for 33 years as the senior pastor of Bethlehem Baptist Church in Minneapolis, Minnesota, and is the author of more than 50 books, including Desiring God, Don't Waste Your Life, This Momentary Marriage, A Peculiar Glory, and Reading the Bible Supernaturally.