The father of Abd al-Rahman bin al-Aswad said: I asked Sayyidah Aishah (may Allah be pleased with her): How was the ablution of the Prophet (peace and blessings be upon him) when he intended to sleep while in a state of janabah? She said: "He (peace and blessings be upon him) would perform an ablution like the ablution for prayer, then sleep."
Sayyidah Aishah (may Allah be pleased with her) said that he (peace and blessings be upon him) would sleep while in a state of janabah and would not touch water.
It is narrated from Ibn Umar (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah, can one of us sleep while in a state of janabah? He (peace and blessings be upon him) said: "Yes, he may sleep after performing ablution."
The Shaykh said: Abu al-Walid narrated to me: I asked Abu al-Abbas bin Shurayh about these two hadiths, and he said: Both narrations have one ruling. In the hadith of Aishah (may Allah be pleased with her), what she meant was that the Prophet (peace and blessings be upon him) would not touch water for the ritual bath. The hadith of Umar (may Allah be pleased with him) is explicit (mufassar), mentioning ablution, and we act upon it.
The hadith of Abu Ishaq al-Sabi'i is sahih (authentic) in terms of narration, because Abu Ishaq made clear that he heard it from al-Aswad in the narration of Zuhayr bin Mu'awiyah from him; and when a mudallis who is thiqah (trustworthy) makes clear that he heard it from the one he narrates from, there is no reason to reject it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 977