Signs of Belonging: Luther's Marks of the Church and the Christian Life

Signs of Belonging: Luther's Marks of the Church and the Christian Life explores Luther's teaching on the seven marks of the church: possession of the Word, Baptism, Sacrament of the Altar, Office of the Keys, Office of Ministry, Discipleship, and the cross (suffering on account of one's faith). How do these "marks" define the corporate body of Christ and connect with the lives of individual Christians?