A daughter of the Messenger of Allah ﷺ sent word to him, while Usama bin Zayd, Saad, and Ubayy, or Ubayy, were with the Messenger of Allah ﷺ, saying, "My son is dying, so come to us."He sent back his greetings of peace and said, "What Allah has taken and what He has given are His, and everything with Him has an appointed term. So let her be patient and seek her reward."She sent to him again, urging him by oath to come, so he stood up and we stood with him. When he sat down, the child was lifted up to him and he placed him in his lap while the child's breath rattled. The eyes of the Messenger of Allah ﷺ overflowed with tears.Saad asked, "What is this, Messenger of Allah?"He replied, "This is a mercy that Allah has placed in the hearts of whomever He wills among His servants. Allah only shows mercy to those of His servants who are merciful."
أن ابنة لرسول الله ﷺ أرسلت إليه- ومع رسول الله ﷺ أسامة بن زيد وسعد وأبي أو أبي- أن ابني قد احتضر، فاشهدنا. فأرسل يقرأ السلام ويقول: إن الله ما أخذ وما أعطى، وكل شيء عنده مسمى فلتصبر وتحتسب. فأرسلت إليه تقسم عليه، فقام وقمنا معه، فلما قعد رفع إليه فأقعده في حجره ونفس الصبي تقعقع، ففاضت عينا رسول الله ﷺ، فقال سعد: ما هذا يا رسول الله؟ قال: هذه رحمة يضعها الله في قلوب من يشاء من عباده، وإنما يرحم الله من عباده الرحماء.
Bukhari narrated it in the Book of Oaths and Vows (6655), and Muslim narrated it in the Book of Funerals (11:923), both through the route of Asim Ahwal, from Abu Uthman Nahdi, from Usama bin Zayd, that the daughter of the Messenger of Allah ﷺ sent a message to him, and he mentioned it.Her statement, "she swears an oath upon him to come," is not actually an oath, because if it had been an oath, he would have instructed her to fulfill it. This is also indicated by the hadith of Ibn Abbas that follows.