Apophthegmata Laconica

Plutarch

Plutarch. Moralia, Vol. III. Babbitt, Frank Cole, translator. Cambridge, MA: Harvard University Press; London: William Heinemann Ltd., 1931 (printing).

When someone said, Why have you not killed off the people of Argos who wage war against you so often? he said, Oh, we would not kill them off, for we want to have some trainers for our young men.