Sahih Bukhari
Sales in which a Price is paid for Goods to be Delivered Later (As-Salam)
Volume: 003 / Book Number: 035 / Hadith Number: 454
Narrated Al-A'mash:
We argued at Ibrahim's dwelling place about mortgaging in Salam. He said, "Aisha said, 'The Prophet bought some foodstuff from a Jew on credit and the payment was to be made by a definite period, and he mortgaged his iron armor to him."