Beyond Good and Evil by Friedrich Nietzsche Chapter 1 Page 45

there were a NECESSITY OF EFFECT; in a word, he who wills believes with a fair amount of certainty that will and action are somehow one; he ascribes the success, the carrying out of the willing, to the will itself, and thereby enjoys an increase of the sensation of power which accompanies all success.

“Freedom of Will” — that is the expression for the complex state of delight of the person exercising volition, who commands and at the same time identifies himself with the executor of the order — who, as such, enjoys also the triumph over obstacles, but thinks within himself that it was really his own will that overcame them. In this way the person exercising volition adds the feelings of delight of his successful executive instruments, the useful “underwills” or under-souls —