Sayyidah Aishah (may Allah be pleased with her) says: After the verse of hijab had been revealed, Sayyidah Sawdah (may Allah be pleased with her) went out for some need of hers. She was a large woman and could not be hidden from anyone who knew her. Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) saw her and said: "By Allah! O Sawdah, you cannot hide from us, so consider how you go out." The narrator says: She turned back at once. the Messenger of Allah (peace and blessings be upon him) was in my room having his evening meal, and there was a bone in his (peace and blessings be upon him) hand. As soon as she came in, Sayyidah Sawdah (may Allah be pleased with her) said: "O Messenger of Allah (peace and blessings be upon him)! I went out to relieve myself and Umar (may Allah be pleased with him) said such-and-such things to me." Then revelation came down upon him (peace and blessings be upon him), and a little later, when that state ended, the bone was still in his (peace and blessings be upon him) hand; he (peace and blessings be upon him) had not put it down. Then he (peace and blessings be upon him) said: "Permission has been given to you to go out to relieve yourselves."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13507