It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her); she said: By the One by whom Umm Salamah swears, the closest of people to the Messenger of Allah (peace and blessings be upon him) was Sayyiduna Ali (may Allah be pleased with him). We were with the Messenger of Allah (peace and blessings be upon him) in the house of Sayyidah Aishah (may Allah be pleased with her), and I was the last of those to leave the house. Then we sat near the door, and Sayyiduna Ali (may Allah be pleased with him) remained bent over him (peace and blessings be upon him); so he was the last to be with him (peace and blessings be upon him), speaking to him (peace and blessings be upon him) in whispers and in confidence.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20189