Lutherans follow a man, Jesus Christ, not a book. The Holy Scriptures testify to the Word Of God becoming flesh in Jesus Christ. The authority of the Lutheran church is rooted in the testimony of scripture.
The Lutheran church reads that testimony through the eyes of the gospel, which is the good news of Jesus Christ who defeated death and bridged the gap between humans and God.
Rev. Kristin Luana Baumann, sermon, Holy Trinity Lutheran Church, Port Angeles WA, 1/8/2016.