Sahih Bukhari
Sales in which a Price is paid for Goods to be Delivered Later (As-Salam)
Volume: 003 / Book Number: 035 / Hadith Number: 456
Narrated Muhammad bin Abi Al-Mujalid:
Abu Burda and 'Abdullah bin Shaddad sent me to 'Abdur Rahman bin Abza and 'Abdullah bin Abi Aufa to ask them about the Salaf (Salam). They said, "We used to get war booty while we were with Allah's Apostle and when the peasants of Sham came to us we used to pay them in advance for wheat, barley, and oil to be delivered within a fixed period." I asked them, "Did the peasants own standing crops or not?" They replied, "We never asked them about it."