Sahih Muslim Book 1, Hadith Number 259.

Chapter : Concerning the fact that violable is the blood of one who makes an attempt to take possession of the property of another without any legitimate right. If such a man is killed his abode is Fire and he who dies in protecting his property is a martyr.

Abu Huraira reported: A person came to the Messenger of Allah (may peace be upon him) and said: Messenger of Allah, what do you think if a man comes to me in order to appropriate my possession? He (the Holy Prophet) said: Don’t surrender your possession to him. He (the inquirer) said: If he fights me? He (the Holy Prophet) remarked: Then fight (with him). He (the inquirer) again said: What do you think if I am killed? He (the Holy Prophet) observed: You would be a martyr. He (the inquirer) said: What do you think of him (Messenger of Allah) If I kill him. He (the Holy Prophet) said: he would be in the Fire.