He was a markedly quiet and reticent person. As his contemporaries describe him, he was a youth of tall stature, friendly manners, and unusually earnest conduct. Denck was an aristocratic personality, in spite of the refugee life imposed upon him. Nor did he show the slightest bitterness at his lot, for he was convinced that this was the price he had to pay for his beliefs. Far from being a rabble rouser, Denck was soft-spoken and inclined to avoid controversy.

Denck had met Thomas Muntzer in Nuremberg, and had learned from him to see a good many questions in a light different from Luther's. The first controversial point was the question of infant baptism, which, Denck pointed out, was never stipulated in the Bible. He himself had been baptized by Balthasar Hubmaier, and he in turn baptized Hans Hut, an important figure in the history of chiliasm.

Denck moved gradually towards the Anabaptist position. He defined baptism as the "covenant of good conscience with God." But it was not of central importance to his religious ideas, as has been alleged. In fact, Denck considered ceremonies in general as superficial and secondary. The imitation of Jesus was what counted; ceremonies were justified only if they furthered love. Anyone who thought to achieve salvation merely by practicing certain forms was steeped in superstition. Inner baptism was far more important than outer baptism. Towards the end of his life Denck went so far as to declare: "Therefore I would not baptize at all."

Far more vital to Denck was the question of a Christian conduct of life. The mode of life is what counts, for "Christ cannot truly recognize anyone who does not imitate him in this life." Denck did not belittle faith; he regarded it as obedience to God. But in the style of the primitive Christians he upheld love as the supreme attitude for the Christian, superior alike to faith and to hope. There was a spark of love in every man, Denck believed; but in these troubled times, he lamented, it had been extinguished in almost all men. Yet no matter how minute this spark might be, it came from the perfect love which was God himself.

Denck also began to think differently about revelation. Protestantism in general considered Scripture the sole source of revelation. Denck, too, esteemed the Bible "above all human treasures," but he did not equate it with God's Word. He was careful not to make an idol out of Holy Scripture. It was, to be sure, the light shining in the darkness, but it could not remove the darkness since it too had been written by human hands. A man illumined by God could achieve salvation even without Holy Scripture. It depended upon the heart; Denck attributed revelatory powers to the spark in the soul, as the medieval mystics had done. The inner light, he said, "speaks clearly in everyone, in the deaf, dumb, and blind, even in unreasoning beasts, even in leaves and grass, stone and wood, heaven and earth, and all that is in them, that they may hear and do his will. In man alone, who does not want to be nothing and yet is even more than nothing, is there resistance to it."

In his discussions of the inner spark, Denck anticipated a first principle of that deeply religious movement to be known as Quakerism. We may well meditate upon Denck's fundamental insight: "It is not enough for God to be in you; you must also be in God."

Denck's independence as a religious thinker also appears in his appreciation of paradox. The perception of truths which can only be communicated to the human mind in the form of contradictions was very much the fashion of that age. Luther had a good deal to say on this question, and Sebastian Franck devoted a whole book to the subject. Denck, too, was much concerned with the paradoxical formulation of Christianity, and in various Gegenschriften (this was the term he coined for paradox) placed side by side such quotations as these:

"I will not be angry for ever." (Jeremiah 3:12)

"And they will go away into eternal punishment." (Matthew 25:46)

He believed that "in matters of faith all must proceed freely, willingly, and unforced." He had not too long to live when he voiced the touching plaint: "It seems to me an unjust law that it should not be permissible for one man to think differently from another." It is to Denck's eternal credit that in his darkest hours he maintained his belief in freedom of thought. He made every effort not to hate his religious adversaries, and he insisted that, although he had been barred from the community of believers, he had not allowed his heart to be turned away from them.

A true religious spirit, not any weakness, underlay his admonition: "But you, if you hear your brothers say something that is strange to you, do not at once contradict, but hear whether it be right, whether you may accept it. If you do not like to hear it, still, do not condemn him, and if it appears to you that he is mistaken, consider whether you may not be more mistaken."