No unchanging custom, no changing evolution can make the original good anything but good. Man may have had concubines as long as cows have had horns: still they are not a part of him if they are sinful. Men may have been under oppression ever since fish were under water; still they ought not to be, if oppression is sinful. The chain may seem as natural to the slave, or the paint to the harlot, as does the plume to the bird or the burrow to the fox; still they are not, if they are sinful.
That evil which has seemed to go on forever can only be deemed evil instead of natural if it is a sin
