The offering of [the body] is called a spiritual sacrifice because it is freely sacrificed through the Spirit, the Christian being uninfluenced by the constrainst of the Low or the fear of hell.
Martin LutherWhen my heart is cold and I cannot pray as I should I scourge myself with the thought of the impiety and ingratitude of my enemies, the Pope and his accomplices and vermin, and Zwingli, so that my heart swells with the righteous indignation and hatred and I can say with warmth and vehemence: 'Holy be Thy Name, Thy Kingdom come, Thy Will be done!' And the hotter I grow the more ardent do my prayers become.
Martin LutherI maintain that some Jew wrote it who probably heard about Christian people but never encountered any.
Martin LutherI often laugh at Satan, and there is nothing that makes him so angry as when I attack him to his face, and tell him that through God I am more than a match for him
Martin LutherWhen our Lord and Master Jesus Christ said, 'Repent,' he willed the entire life of believers to be one of repentance.
Martin LutherWe conclude, therefore, that a Christian lives not in himself, but in Christ and in his neighbor. Otherwise he is not a Christian. He lives in Christ through faith, in his neighbor through love. By faith he is caught up beyond himself into God. By love he descends beneath himself into his neighbor.
Martin Luther