Musnad Ahmad Hadith 21776

It is narrated from Usama (may Allah be pleased with him) that once a daughter of the Noble Prophet (ﷺ) sent a message to the service of the Noble Prophet (ﷺ) that her child was in the throes of death, and requested that he come to them. The Noble Prophet (ﷺ) sent his greetings to her and said: "What He takes belongs to Allah, and what He gives belongs to Allah, and everything has an appointed time with Him. Therefore, you should be patient and hope for reward upon this." She again sent a messenger to the Noble Prophet (ﷺ), insisting by oath. So the Noble Prophet (ﷺ) stood up, and we also stood up with him. The child was brought and placed in the lap of the Noble Prophet (ﷺ), and his soul was departing. Among the people present at that time were Sa'd bin Ubadah (may Allah be pleased with him) and, it seems, Ubayy (may Allah be pleased with him) as well. Tears began to flow from the eyes of the Noble Prophet (ﷺ). Seeing this, Sa'd (may Allah be pleased with him) said, "O Messenger of Allah! What is this?" He replied, "This is mercy, which Allah places in the hearts of whichever of His servants He wills. And Allah shows mercy only to those of His servants who are merciful."