Johann Arndt (1555–1621) was a German Lutheran pastor and theologian who wrote “True Christianity,” a significant book on devotional Christianity. This year is the 400th anniversary of his death. He was born on Dec. 27, 1555, at Ballenstedt in Anhalt, Germany. His parents, Jakob and Anna Sochtings Arndt, had Johann and his two younger siblings. Johann’s father was ordained in…