… is from the fifth-century B.C. Chinese philosopher Mozi , whose writing on war  I learned about while reading Michael Huemer’s superb 2013 book, The Problem of Political Authority ; on page 337 Huemer quotes part of the passage below :
To kill one man is to be guilty of a capital crime, to kill ten men is to increase the guilt ten-fold, to kill a hundred men is to increase it a hundred-fold. This the rulers of the earth all recognize and yet when it comes to the greatest crime – waging war on another state – they praise it! It is clear they do not know it is wrong, for they record such deeds to be handed down to posterity; if they knew they were wrong, why should they wish to record them and have them handed down to posterity? If a man on seeing a little black were to say it is black, but on seeing a lot of black were to say it were white, it would be clear that such a man could not distinguish between black and white.