Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates that the Noble Prophet (peace and blessings of Allah be upon him) said: "Qisas (retaliation) will only be taken when the killing is done with a sword, and in the case of accidental killing, the payment of blood money will be upon the family of the killer." It is narrated in the same way from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him).