XX. (96) Then, O you most worthless of all men! I would say to them, have you not first learnt what you are now teaching? or do you know how to invite other people to compassion even by the most inhuman actions, and yet have you eradicated all merciful and humane feelings from your own souls? And do you act in this way in spite of not being in want of good advisers, and especially of our laws, which have released even the earth from its yearly burdens, giving it a relaxation and a respite? (97) and it, although it seems to be inanimate, is nevertheless fully prepared to make a requital and to recompence favours, hastening to pay back any gift which it has received; for as it receives an exemption every seventh year, and is not forced to exert itself that year, but is set wholly free for the whole circle of the year, in the subsequent year produces double, or sometimes, many times, larger crops than usual from its great productiveness. (98) And in like manner you may see the trainers acting in the same way towards the athletes; for when they are exercising them with continual and uninterrupted practice, before they are wholly knocked up, they refresh them, giving a respite not only from their exertions in training, but also from their strict regimen of eating and drinking, relaxing the severity of their diet so as to produce a cheerfulness of soul and good condition of body. (99) And yet they are not to be looked upon as teachers of indolence and luxury, inasmuch as their professed business is to train men to the endurance of labours, but by a certain method and artificial system they add to their natural strength a strength more powerful still, and to their innate vigour a more energetic vigour still, increasing their previous powers by reciprocal remission and exertion, as by a well-regulated harmony. (100) And I have learnt all this from all-wise nature, which, knowing the industrious and laborious condition of our race, has distributed them into day and night, giving to us the one for wakefulness, and the other for sleep; (101) for she felt a natural anxiety, like a careful mother, that her offspring should not be worn out with toil; for by day she excites our bodies, and rouses them up to all the necessities and duties belonging to life, compelling those to work who would gladly be accustomed to cultivate the leisure of idleness, and an effeminate and luxurious life. But by night, as if she were sounding a retreat in time of war, she invites us to rest, and to take care of our bodies. (102) And those men who have laid aside a heavy weight of business, which has lasted from morning till evening, do now lay their burdens aside and return home and devote themselves to ease, and indulging in profound sleep, refresh themselves after the labours of the day. (103) This long interval between sleeping and waking nature has allotted to men, that they may by turns labour diligently and by turns rest, so as to have all the parts of their bodies more ready for action, and more active and powerful.