Sahih Bukhari
Transferance of a Debt from One Person to Another (Al-Hawaala)
Volume: 003 / Book Number: 037 / Hadith Number: 493
Narrated Jabir bin 'Abdullah:
Once the Prophet said (to me), "If the money of Bahrain comes, I will give you a certain amount of it." The Prophet had breathed his last before the money of Bahrain arrived. When the money of Bahrain reached, Abu Bakr announced, "Whoever was promised by the Prophet should come to us." I went to Abu Bakr and said, "The Prophet promised me so and so." Abu Bakr gave me a handful of coins and when I counted them, they were five-hundred in number. Abu Bakr then said, "Take twice the amount you have taken (besides)."