From Sahih Bukhari (Hadith 2252):
Narrated Al-A`mash:We argued at Ibrahim's dwelling place about mortgaging in Salam. He said, "Aisha said, 'The Prophet (ﷺ) 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
Reference: Bukhari 2252