Umm Sulaim Al Rumaisa said “The Prophet ﷺ slept and awoke while she was washing her head. ” He awoke laughing. She asked “Messenger of Allah ﷺ are you laughing at my head?” He replied, No. She then narrated the rest of the tradition enlarging and reducing. Abu Dawud said: Al-Rumaisa was the foster sister of Umm Sulaim.
Hadith Referenceسنن ابي داود / كتاب الجهاد / 2492
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح
Hadith Takhrij« انظر حدیث رقم : (2490)، (تحفة الأشراف: 18307) (صحیح) »
Brief Explanation
1؎: Umm Sulaym radi Allahu anha is the sister of Umm Haram bint Milhan radi Allahu anha; in the chain of narration, "the sister of Umm Sulaym" refers to Umm Haram bint Milhan radi Allahu anha herself. Umm Haram radi Allahu anha was called Ramisa, and Umm Sulaym radi Allahu anha was called Ghumaisa.
2؎: This statement of Abu Dawud is not correct; they were not foster sisters but rather sisters by lineage and in reality.