De liberis educandis

Now there is another point which should not be omitted, that in choosing the younger slaves, who are to be the servants and companions of young masters, those should be sought out who are, first and foremost, sound in character, who are Greeks as well, and distinct of speech, so that the children may not be contaminated by barbarians and persons of low character, and so take on some of their commonness. The proverb-makers say, and quite to the point, If you dwell with a lame man, you will learn to limp.