Martin Luther (1483–1546).
De libertate christiana, dissertatio … epistola eiusdem ad Leonem Decimum summum pontificem.
Basel: Adam Petri, 1521.
In contrast to the highly polemical “Prelude on the Babylonian Captivity of the Church,” De libertate christiana (“On the Freedom of a Christian”), also first published in Wittenberg in 1520, was composed in a more conciliatory tone and included a prefatory letter to Pope Leo X. Discussing the concept of Christian liberty, Luther succinctly presented his fundamental doctrine of justification by faith alone (sola fide), through which God's pardon for guilty sinners is granted and received by faith alone. Luther conceived this freedom as both liberating individual Christians from the Church and restricting those same worshippers due to the necessity of self-discipline and the obligation of serving others. In this treatise, Luther stated, "A Christian is a perfectly free lord of all, subject to none. A Christian is a perfectly dutiful servant of all, subject to all."