It is narrated from Ibn Abi Sagheer that the Prophet (peace be upon him) looked at the martyrs of Uhud and said: I am a witness over them, cover them with their blood and wounds.
Hadith Referenceمسند الإمام الشافعي / كتاب الجنائز / 570
Hadith Takhrijصحيح : اخرجه البيهقي في المعرفة السنن والآثار (2094) ۔ واحمد : 431/8 ـ وعبد الرزاق (6633) ۔ وسعيد بن منصور (2584)۔