Sahih Muslim
The Book Pertaining to the Oath, for Establishing the Responsibility of Murders, Fighting, Requital and Blood-Wit (Kitab Al-Kitab Al-Qasama wal-Muharaba wal-Qisas wal-Diyat)
Book Number: 016 / Hadith Number: 4156
'Abdullah (b. Mas'ud) reported: Allah's Apostle (may peace be upon him) having said: No person who is killed unjustly, but the share of (this offence of his also) falls upon the first son of Adam, for he was the first to introduce killing.