Narrated Aisha: Sauda (the wife of the Prophet) went out to answer the call of nature after it was made obligatory (for all the Muslims ladies) to observe the veil. She was a fat huge lady, and everybody who knew her before could recognize her. So `Umar bin Al-Khattab saw her and said, "O Sauda! By Allah, you cannot hide yourself from us, so think of a way by which you should not be recognized on going out. Sauda returned while Allah's Messenger was in my house taking his supper and a bone covered with meat was in his hand. She entered and said, "O Allah's Messenger! I went out to answer the call of nature and `Umar said to me so-and-so." Then Allah inspired him (the Prophet) and when the state of inspiration was over and the bone was still in his hand as he had not put in down, he said (to Sauda), "You (women) have been allowed to go out for your needs."

Narrated `Aisha: The wives of the Prophet used to go to Al-Manasi, a vast open place (near Baqi at Medina) to answer the call of nature at night. `Umar used to say to the Prophet "Let your wives be veiled," but Allah's Apostle did not do so. One night Sauda bint Zam`a the wife of the Prophet went out at `Isha' time and she was a tall lady. `Umar addressed her and said, "I have recognized you, O Sauda." He said so, as he desired eagerly that the verses of Al-Hijab (the observing of veils by the Muslim women) may be revealed. So Allah revealed the verses of "Al-Hijab" (A complete body cover excluding the eyes).

Narrated `Aisha: Once Sa`da bint Zam`a went out at night for some need, and `Umar saw her, and recognizing her, he said (to her), "By Allah, O Sa`da! You cannot hide yourself from us." So she returned to the Prophet and mentioned that to him while he was sitting in my dwelling taking his supper and holding a bone covered with meat in his hand. Then the Divine Inspiration was revealed to him and when that state was over, he (the Prophet was saying: "O women! You have been allowed by Allah to go out for your needs."