He who is running a race ought to endeavor and strive to the utmost of his ability to come off victor; but it is utterly wrong for him to trip up his competitor, or to push him aside. So in life it is not unfair for one to seek for himself what may accrue to his benefit; but it is not right to take it from another.
ChrysippusThere could be no justice, unless there were also injustice; no courage, unless there were cowardice; no truth, unless there were falsehood.
Chrysippus