Ayatana

"Monks, you should dwell with the doors to your senses well-guarded.On seeing a form with the eye, do not grasp at any theme or details by which — if you were to dwell without restraint over the faculty of the eye — evil, unskillful qualities such as greed or distress might assail you. Practice for its restraint. Guard the faculty of the eye. Secure your restraint with regard to the faculty of the eye."

"Bhikkhus, you should train thus: 'We will guard the doors of our sense faculties. On seeing a form with the eye, we will not grasp at its signs and features. Since, if we left the eye faculty unguarded, evil unwholesome states of covetousness and grief might invade us, we will practice the way of its restraint, we will guard the eye faculty, we will undertake the restraint of the eye faculty.'"