Cobbler

Let not the cobbler overstep his last (Ne suʹtor ultra crepʹidam). Let no one presume to interfere in matters of which he is ignorant. The tale goes that a cobbler detected a fault in the shoe-latchet of one of Apellesʹ paintings, and the artist rectified the fault. The cobbler, thinking himself very wise, next ventured to criticise the legs; but Apelles answered, “Keep to your trade”—you understand about shoes, but not about anatomy.