The Lutheran Church Missouri Synod (LCMS) is a collection of Lutheran churches who all subscribe to the Bible as the infallible, inerrant, and inspired Word of God, and the sole highest authority in doctrine.
With this in mind, the LCMS puts its full trust in God's Word, as it was given to us by God, without any need for us to add, remove, or otherwise update in its content and teaching. The LCMS also holds to the Book of Concord as the correct summary and explanation of God's Word, because it is such.
The mission statement of the LCMS is this:
In grateful response to God’s grace and empowered by the Holy Spirit through Word and Sacraments, the mission of The Lutheran Church—Missouri Synod is vigorously to make known the love of Christ by word and deed within our churches, communities and the world.