2. A number of our people have narrated from Sahl ibn Ziyad from Muhammad ibn ‘Isa from Muhammad ibn Ali al-Hamadaniy from Hanan ibn Sadir who has said the following: “I once visited abu ‘Abd Allah , and I wore a black shoe. He (the Imam) said, ‘O Hanan, what do you have to do with black (color)? Did you not know that it has three disadvantages ? It weakens the eye sight, slackens the penis and causes anxieties [and besides it is of footgear of tyrants]?’ I then asked, ‘What kind of shoe must I wear?’ He (the Imam) said, ‘You must wear yellow because it has three qualities. It brightens eyesight, hardens the penis, dispels anxieties and besides it is of the footgear of the Prophets.’”