How sound is the statement of Halimah As-Sa'diyah: "We have no lamp in the dark nights save for his face"?

The aforementioned hadith about the Messenger of Allah, peace and blessings be upon him, illuminating the room with his face, has not been found. However, hadiths describe his face, peace and blessings be upon him, as beautiful and radiant, as if it were the moon on its full night or as if the sun coursed through it. It is also mentioned that he would light up when pleased, due to his beauty and radiance, not due to a physical illumination of the room. Indeed, Aisha, may Allah be pleased with her, would search for him in the dark and feel for him with her hand.