Knoop was among those within the Dutch Reformed Church who refused to compromise with the Nazi occupying authorities. After months of intimidation and threats, and hostility from those within the church who were willing to compromise with Nazi efforts to employ the church in its service, thereby removing the offense of the gospel from its message and advacing its own agenda, Knoop was arrested on November 19, 1941 in Rotterdam. After sentencing and transfers, Knoop was sent to KZ-Dachau where he stayed from April 25, 1942 to October 9, 1943. Amazingly, he was released and went on the resume his pastoral duties.
In his autobiographical memoir, Een Theater in Dachau (A Theatre in Dachau), he wrote of how hunger changes a man, how medical experiments were performed on him, how torture reaches the limits of endurance and somehow exceeds them, how godlessness reigned in that horrible dark place. The story is shocking, even to those who are acquainted distantly with the events that occurred there. But what is most wonderful to read, even to those who know the power of God in their lives personally, and how his light shines in the darkest of hearts, is Knoop's testimony to the grace of God which was at work in Dachau. Like the Apostle Paul, who was "made a spectacle unto the world, and to angels, and to men" (1 Cor. 4.9), the witness of Christ in that darkest of prison holes was made a spectacle, a theater, to the world, showing forth God's grace. Knoop was imprisoned for his faith in Christ, and though he spent a year and a half in a man-made hell, God did not leave him, but is greatly magnified in the story of his life.
Whither shall I go from thy spirit? or whither shall I flee from thy presence? If I ascend up into heaven, thou art there: if I make my bed in hell, behold, thou art there. (Ps. 139.7-8)
Indeed, in Dachau the God of all grace did wonders of grace by His Word and Spirit every day. Oh, it was indeed a dreadful time for me that I spent there, and yet it is not at all a hollow phrase when I say that I would for no amount of money have missed this time of my life, since it was so unspeakably rich in grace. I saw God there. The Lord was in this place. It was a house of God and a gate of heaven.
It is worth taking special note of the fact that Knoop, like the other prisoners, was not permitted to have access to a Bible during his time at Dachau. This forced him to rely upon the Scriptural passages and Psalms that he had memorized in times past. He wrote of the treasure that he was able to draw upon, having 'hid' the Word of God in his heart (Ps. 119.11). What a testimony to the value of Scriptural memorization.
Being deprived of my Bible was a heavy cross to bear. What riches of comfort I had received out of that Book during my stay in prison! It had been a fountain of strength to me! How the Holy Spirit had strengthened my faith by means of the Word! For there is, of course, no more restful living than in company with, and by the guidance of, the Word. Every day anew my hunger and thirst was to have my faith strengthened through the work of the Spirit by means of the Holy Gospel. But now I did not have a Bible anymore. How I missed it! Thus through this lack of the Bible, I was, as far as the Word of God was concerned, compelled to depend wholly on my memory. Never was I so glad that in my youth my parents had made me memorize so many passages, Psalms, songs, and hymns. I often grumbled about it at the time, of course. But now I experienced the blessing of it all.
The story of Hermanus Knoop in Dachau is a testimony to the truth told by Thomas Brooks (The Mute Christian Under the Smarting Rod) and Karl Bogatzky (Golden Treasury for the Children of God) that "Stars shine brightest in the darkest nights." As the cross represents both the worst, darkest depravity of men and the highest, deepest measure of God's grace, so Knoop's account of Dachau shows forth the worst suffering and the most wonderful grace of God.
Soon after he was first arrested, a poem was written about this prisoner of faith by Mrs. C.E.T. Luykenaar Francken-Schreuder. I record here the English version, translated by Roelof A. Janssen.
He did not fear those who could kill the body,
Slowly murdering him in prison,
Or with a bullet, businesslike and quick;
He spoke that which Thou to him had bidden.
Now they have caught him in their cage.
But by singing prayer he frees his soul
Far above all hatred, mocking, and sympathy,
He flees to Thee, his highest goal.
They can bind -- but the Word stays free;
They can kill -- but the Saviour lives.
And with Him, freed of sin and ties,
Live those to whom He of His Spirit gives.
Thus grant all of us this comfort,
Which strengthens while mocked in loneliness.
For he who suffers for the sake of Christ,
Thou wilt preserve in eternal blessedness.