"Error and heresy must come into the world so that the elect may become approved and manifest. Their coming is in the best interests of Christians if they take the proper attitude toward it. St. Augustine, who certainly was sufficiently annoyed by wretched sectaries, says that when heresy and offense come, they produce much benefit in Christendom; for they cause Christians industriously to read Holy Scriptures and with diligence to pursue it and persevere in its study. Otherwise they might let it lie on the shelf, become very secure, and say: Why, God's Word and the text of Scripture are current and in our midst; it is not necessary for us to read Holy Scripture."
What Luther Says, An Anthology, 3 vols., ed., Ewald Plass, St. Louis: Concordia Publishing House, 1959, II, p. 639.
KJV 1 Corinthians 11:19 For there must be also heresies among you, that they which are approved may be made manifest among you.
