وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، قَالَ لَمَّا كَانَ يَوْمُ أُحُدٍ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ مَنْ يَأْتِينِي بِخَبَرِ سَعْدِ بْنِ الرَّبِيعِ الأَنْصَارِيِّ ‏"‏ ‏.‏ فَقَالَ رَجُلٌ أَنَا يَا رَسُولَ اللَّهِ ‏.‏ فَذَهَبَ الرَّجُلُ يَطُوفُ بَيْنَ الْقَتْلَى فَقَالَ لَهُ سَعْدُ بْنُ الرَّبِيعِ مَا شَأْنُكَ فَقَالَ لَهُ الرَّجُلُ بَعَثَنِي إِلَيْكَ رَسُولُ اللَّهِ صلى الله عليه وسلم لآتِيَهُ بِخَبَرِكَ ‏.‏ قَالَ فَاذْهَبْ إِلَيْهِ فَأَقْرِئْهُ مِنِّي السَّلاَمَ وَأَخْبِرْهُ أَنِّي قَدْ طُعِنْتُ اثْنَتَىْ عَشْرَةَ طَعْنَةً وَأَنِّي قَدْ أُنْفِذَتْ مَقَاتِلِي وَأَخْبِرْ قَوْمَكَ أَنَّهُ لاَ عُذْرَ لَهُمْ عِنْدَ اللَّهِ إِنْ قُتِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَوَاحِدٌ مِنْهُمْ حَىٌّ ‏.‏

Yahya related to me from Malik that Yahya ibn Said said, "On theDay of Uhud, The Messenger of Allah, may Allah bless him and grant himpeace, said, 'Who will bring me news of Sad ibn al-Rabi al-Ansari?' aman said, 'Me, Messenger of Allah!' So the man went around among theslain, and Sad ibn al-Rabi said to him, 'What are you doing?' The mansaid to him, 'The Messenger of Allah, may Allah bless him and granthim peace, sent me to bring him news of you.' He said, 'Go to him, andgive him my greetings, and tell him that I have been stabbed twelvetimes, and am mortally wounded. Tell your people that they will haveno excuse with Allah if the Messenger of Allah, may Allah bless himand grant him peace, is slain while one of them is still alive.' " Translation Not Available

Book Ref: Muwatta Imam Malik Book 21 Hadith 1001
Web Ref:  Muwatta Imam Malik Book 21 Hadith 41