Nahj al-Balagha (Peak of Eloquence)

466. Amīr al-mu’minīn, peace be upon him, said: The eye is the strap of the rear. as-Sayyid ar-Raḍī says: This is a wonderful metaphor, it is as though Amīr al-mu’minīn has likened the rear part of the body with a bag and the eye with a strap. When the strap is let loose the bag cannot retain anything. According to the well-known and reputed view it is the saying of the Prophet but some people have stated it to be of Amīr al-mu’minīn. al-Mubarrad has mentioned it in his book al-Muqtaḍab under the chapter ‘Words of single letters’. We too have discussed this metaphor in our book named Majāzāt al-āthār an-nabawiyyah.