The Messenger of Allah ﷺ rose one night, put on his clothes, and went out. So I instructed my servant girl Barirah to follow him. She followed him until he came to al-Baqi, where he stood at its near edge for as long as Allah willed, then turned back. Barirah hurried back ahead of him and told me what she had seen. I said nothing to him about it until morning came, and then I mentioned it to him.He said, "I was sent to the people of al-Baqi to pray for them."
أخبرني محمد بن سلمة والحارث بن مسكين قراءة عليه وأنا أسمع واللفظ له عن ابن القاسم قال حدثني مالك عن علقمة بن أبي علقمة عن أمه أنها
قام رسول الله ﷺ ذات ليلة فلبس ثيابه ثم خرج قالت فأمرت جاريتي بريرة تتبعه فتبعته حتى جاء البقيع فوقف في أدناه ما شاء الله أن يقف ثم انصرف فسبقته بريرة فأخبرتني فلم أذكر له شيئا حتى أصبحت ثم ذكرت ذلك له فقال إني بعثت إلى أهل البقيع لأصلي عليهم
[Its isnad is hasan]. Ahmad reported it (6/92) from the hadith of Alqama through this chain. It is also in Kubra, no. 2165, and in Muwatta (Yahya), 1/242, p. 416, no. 405, the narration of Abdul-Rahman bin Qasim. Hakim graded it sahih (1/488) and Dhahabi agreed with him. Its narrators are trustworthy, and I have not seen a strong argument for anyone who declared it daif.