In his Theses against the sale of indulgences, especially in the first two, Luther had uttered a thought which led to a new conception of the Church.  He had declared that Christian life does not consist in the performance of certain works of piety, such as going to confession, performing the penances imposed by priests, hearing Mass, etc.,—­all of which are external, visible acts,—­but in a continuous penitential relation of the heart to God.  The Christian, conscious of his innate corruption and his daily sinning, faces God at all times in the attitude of a humble suitor for mercy.  The posture of the publican is the typical attitude of the Christian.  He recognizes no merit in himself, he pleads no worthiness which would give him a just claim upon God’s favor.  His single hope and sole reliance is in the merit and atoning work of his Savior Jesus Christ.  The Christian’s penitence embraces as a constituent element faith in the forgiveness of sin for Christ’s sake.  In the strength of his faith the Christian begins to wrestle with the sin which is still indwelling in him and which besets him from without.  The agony of the Redeemer which he places before his eyes at all times proves a deterrent from sin, and the holy example of Jesus, who ran with rejoicing the way of the commandments of God, becomes an inspiring example to him:  actuated by gratitude for the love of the Son of God who gave Himself for him and reclaimed him from certain perdition, he begins to reproduce the life of Jesus in his own conversation.  His whole life is determined by his relation to Jesus:  his thoughts, affections, words, and deeds are a reflex of the life of his Lord.  For him to live is Christ (Phil. 1, 21).  All his acts become expressions of his faith.  He says with Paul:  “I live; yet not I, but Christ liveth in me:  and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave Himself for me” (Gal. 2, 20).

During the discussions which followed the publication of the Theses, especially during the Leipzig Debate with Eck in 1519, this thought of Luther was expanded, and applied to the idea of the Church.  Christianity, in Luther’s teaching, came to be set forth as something vastly different from the external and mechanical religiousness which had been accepted as Christianity by Rome.  Christianity meant a new life, swayed by new motives, governed by new principles.  It was seen to be entirely inward, an affair of the heart and soul and mind, and, ulteriorly, an affair of the body and the natural life.  The religion of Rome, with its constant emphasis on works of men’s piety and the merit resulting therefrom, had become thoroughgoing externalism.  So many prayers recited, so many altars visited, so many offerings made, meant so many merits achieved.  The scheme worked out with mathematical precision.  Devout Catholics might well keep a ledger of their devotional acts, as Gustav Freitag in his Ancestors represents Marcus Koenig as having done.