question #1 Sahih al-Bukhari 2244, Book 35, Hadith 7 : What is the practice of paying in advance for goods in Islamic trade, and how was it conducted during the Prophet’s time?

`Abdullah bin Shaddad and Abu Burda sent me to `Abdullah bin Abi `Aufa and told me to ask
`Abdullah whether the people in the lifetime of the Prophet (ﷺ) used to pay in advance for wheat (to be
delivered later). `Abdullah replied, “We used to pay in advance to the peasants of Sham for wheat,
barley and olive oil of a known specified measure to be delivered in a specified period.” I asked (him),
“Was the price paid (in advance) to those who had the things to be delivered later?” `Abdullah bin
`Aufa replied, “We did not use to ask them about that.” Then they sent me to `Abdur Rahman bin
Abza and I asked him. He replied, “The companions of the Prophet (ﷺ) used to practice Salam in the
lifetime of the Prophet; and we did not use to ask them whether they had standing crops or not.”