In particular, the denial of free will was to Luther the foundation of the Biblical doctrine of grace, and a hearty endorsement of that denial was the first step for anyone who would understand the Gospel and come to faith in God. The man who has not yet practically and experimentally learned the bondage of his will in sin has not yet comprehended any part of the Gospel" (44-45,).
"Justification by faith only is a truth that needs interpretation. The principle of sola fide [by faith alone] is not rightly understood till it is seen as anchored in the broader principle of sola gratia [by grace alone]; . . for to rely on one’s self for faith is not different in principle from relying on one’s self for works" (59,).
"[John] the Baptist's word means that man can receive nothing unless given him from above; so that free-will is nothing!" Martin Luther,
Martin Luther, Bondage of the Will