Some people are sharp and others dull; some are raised in a better environment, others in worse, the latter, having inferior habits and nurture, will require more by way of proof and careful instruction to master these teachings and to be formed by them — in the same way that bodies in a bad state must be given a great deal of care when perfect health is sought.

— Musonius Rufus, Lectures, 1.1.33-1.3.1-3 (resouce) Ryan Holiday, The Daily Stoic