Sunan an-Nasa'i 1868
It was narrated that Abu 'Uthman said:
"Usamah bin Zaid told me: 'The daughter of the Prophet sent word to him telling him: A son of mine is dying, come to us. He sent word to her, conveying his greeting of salam and saying: "To Allah belongs that which He takes and that which He gives, and everything has an appointed time with Allah. Let her be patient and seek reward." She sent word to him adjuring him to go to her. So he got up and went, accompanied by Sa'd bin 'Ubadah, Muadh bin Jabal, Ubayy bin Kab Zaid bin Thabit and some other men. The boy was lifted up to the Messenger of Allah, with the death rattle sounding in him, and his eyes filled with tears. Sa'd said: "O Messenger of Allah, what is this?" he said: "This is compassion which Allah has created in the hearts of His slaves. Allah has mercy on His compassionate slaves."
أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ عَاصِمِ بْنِ سُلَيْمَانَ، عَنْ أَبِي عُثْمَانَ، قَالَ حَدَّثَنِي أُسَامَةُ بْنُ زَيْدٍ، قَالَ أَرْسَلَتْ بِنْتُ النَّبِيِّ صلى الله عليه وسلم إِلَيْهِ أَنَّ ابْنًا لِي قُبِضَ فَأْتِنَا ‏.‏ فَأَرْسَلَ يَقْرَأُ السَّلاَمَ وَيَقُولُ ‏"‏ إِنَّ لِلَّهِ مَا أَخَذَ وَلَهُ مَا أَعْطَى وَكُلُّ شَىْءٍ عِنْدَ اللَّهِ بِأَجَلٍ مُسَمًّى فَلْتَصْبِرْ وَلْتَحْتَسِبْ ‏"‏ ‏.‏ فَأَرْسَلَتْ إِلَيْهِ تُقْسِمُ عَلَيْهِ لَيَأْتِيَنَّهَا فَقَامَ وَمَعَهُ سَعْدُ بْنُ عُبَادَةَ وَمُعَاذُ بْنُ جَبَلٍ وَأُبَىُّ بْنُ كَعْبٍ وَزَيْدُ بْنُ ثَابِتٍ وَرِجَالٌ فَرُفِعَ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم الصَّبِيُّ وَنَفْسُهُ تَقَعْقَعُ فَفَاضَتْ عَيْنَاهُ فَقَالَ سَعْدٌ يَا رَسُولَ اللَّهِ مَا هَذَا قَالَ ‏"‏ هَذَا رَحْمَةٌ يَجْعَلُهَا اللَّهُ فِي قُلُوبِ عِبَادِهِ وَإِنَّمَا يَرْحَمُ اللَّهُ مِنْ عِبَادِهِ الرُّحَمَاءَ ‏"‏ ‏.‏