Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Amr bin Fulan Al-Ansari (may Allah be pleased with him), he says that he was walking in such a state that his lower garment (izar) was hanging below his ankles, when suddenly the Messenger of Allah (peace and blessings be upon him) met him, and at that time the Prophet (peace and blessings be upon him) was holding his forehead and saying: "O Allah! I am Your servant, the son of Your servant, and the son of Your maidservant." Amr says: I said, "O Messenger of Allah! My shins are thin." The Prophet (peace and blessings be upon him) said: "Amr! Indeed, Allah Almighty has created everything beautifully. O Amr!" Then the Messenger of Allah (peace and blessings be upon him) placed the four fingers of his right hand below Amr's knee and said: "This is the place for the izar." Then he lifted them and placed four fingers (the width of the previous four fingers) below, and said: "This is the place for the izar." Then he lifted them and placed them below the second set of four fingers and said: "Amr! This is the place for the izar."