Therefore he says in opposition to both: “I am neither afraid of you, nor will I rejoice with you, for there are other things that I fear and other things in which I will rejoice; I fear Him who can destroy into hell, and not the princes who kill the body (Matt. 10:28). And I will rejoice at the words of God, and not at the presence of your pleasure.” He compares himself to one finding many spoils. And how does he rejoice, I ask? I think that he rejoices in the manner which the Lord describes in Matt. 13:44, that a man who found a treasure hidden in a field hid it and went for joy, etc. He rejoices, but not openly. He alone knows his joy, because he alone knows his good. If he had published it, then the field would certainly not have been sold to him, and he would not have gained possession of the treasure. Or if he had possessed it, he would have possessed it with danger. Such is the joy of the Spirit, because it is in secret, because he alone knows, because also he alone knows his spiritual good. (Luther’s Works, v. 11, p.519)