Is Lutheranism the Only True Religion?

"Do Lutherans believe theirs is the only true religion?" This question was once put to the late Dr. Elson Ruff, editor of The Lutheran. His answer was, "Yes, but Lutherans don't believe they are the only ones who have it.  There are true Christian believers in a vast majority of the churches, perhaps in all."  The ELCA Confession of Faith says "This church confesses Jesus Christ as Lord and Savior and the Gospel as the power of God for the salvation of all who believe