Sahih Muslim Book 1, Hadith Number 209.

Chapter : Strict forbiddance of acting unfaithfully in relation to the spoils or booty. The believers alone would enter Paradise.

It is narrated on the authority of ‘Umar b. Khattab that when it was the day of Khaibar a party of Companions of the Apostle (may peace be upon him) came there and said: So and so is a martyr, till they happened to pass by a man and said: So and so is a martyr. Upon this the Messenger of Allah remarked: Nay, not so verily I have seen him in the Fire for the garment or cloak that he had stolen from the booty, Then the Messenger of Allah (may peace be upon him) said: Umar son of Khattab, go and announce to the people that none but the believers shall enter Paradise. He (‘Umar b. Khattab) narrated: I went out and proclaimed: Verily none but the believers would enter Paradise.