Musannaf Ibn Abi Shayba 18:1318

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Ayyub, from Humayd ibn Hilal, from Hujayr ibn al-Rabi’, who said: I said to ‘Imran ibn Husayn: "What do you see if someone enters upon me wanting my life and my wealth?" He said: "If someone entered upon me wanting my life and my wealth, I would consider that killing him has become lawful for me."