Usama bin Zayd reported,

A daughter of the Prophet ﷺ sent word to him saying that her son was dying and asking him to come to them. He sent back greetings of peace and said, "To Allah belongs what He takes and to Allah belongs what He gives, and everything with Him has an appointed term."She sent word to him again, urging him by oath to come. So he stood up, and we stood with him, along with Muaz bin Jabal, Ubayy bin Kaab, and Saad bin Ubada. The child was handed to him, his soul rattling in his chest, and the Prophet's eyes filled with tears.Saad asked, "Messenger of Allah, what is this?"He replied, "This is mercy that Allah has placed in the hearts of His servants. Allah shows mercy only to those of His servants who are merciful."

حدثنا عبد الرزاق أخبرنا سفيان عن عاصم عن أبي عثمان النهدي

عن أسامة بن زيد قال

أرسلت ابنة النبي ﷺ أن ابني يقبض فأتنا فأرسل بإقراء السلام ويقول لله ما أخذ ولله ما أعطى وكل شيء عنده بأجل مسمى قال فأرسلت إليه تقسم عليه ليأتين قال فقام وقمنا معه معاذ بن جبل وأبي بن كعب وسعد بن عبادة قال فأخذ الصبي ونفسه تقعقع قال فدمعت عيناه فقال سعد يا رسول الله ما هذا قال هذه رحمة جعلها الله في قلوب عباده وإنما يرحم الله من عباده الرحماء