Rathopama Sutta
Endowed with three virtues a monk lives happily in this very life and has laid a foundation for the destruction of the corruptions (āsava). What three? He guards the sense faculties, he is moderate in eating, and devoted to wakefulness.
How does he guard the sense faculties? Having seen a form with the eye, he does not grasp its signs and features. If he left the eye unguarded, unwholesome states of covetousness (abhijjhā) or sorrow (domanassa) might invade his mind so he practices restraint. Having heard a sound with the ear … smelt a scent with the nose … tasted a flavour with the tongue … felt a contact with the body .. cognised an idea with the mind.
As when a chariot, with the horses harnessed, and with a whip ready, is standing at the crossroads on level ground, a skilled charioteer can go wherever he wishes.
How is he moderate in eating? He eats, reflecting wisely, not for pleasure, not for fattening or beautification, but only to sustain the body and keep it healthy and to avoid feelings of discomfort due to hunger.
As ointment is used to heal a wound, or as grease is used on an axle to reduce friction, so a monk eats in moderation.
How is he devoted to wakefulness? By sitting and walking during the day, a monk purifies his mind of obstructive states. During the first watch of the night (6:00 pm to 10:00 pm) also he practises meditation. In the middle watch (10:00 pm to 2:00 am) he lies down mindfully in his right side, after determining the time to arise, he sleeps. In the last watch of the night (2:00 am to 6:00 am) he rises, then sits and walks back and forth, purifying his mind of obstructive states.
Endowed with these three virtues, a monk lives happily in this life and has laid the foundation for the destruction of the corruptions. S.iv.175.