The Kingdom of God is Within You by Leo Tolstoy Chapter 12 Page 122

Had not they some means of stifling their conscience, not one of them would be capable of committing a hundredth part of such a villainy.

It is not that they have not a conscience which forbids them from acting thus, just as, even three or four hundred years ago, when people burnt men at the stake and put them to the rack they had a conscience which prohibited it; the conscience is there, but it has been put to sleep — in those in command by what the psychologists call auto-suggestion; in the soldiers, by the direct conscious hypnotizing exerted by the higher classes.

Though asleep, the conscience is there, and in spite of the hypnotism it is already speaking in them, and it may awake.

All these men are in a position like that of a man under