Muwatta 1927

Malik says: whoever advances gold or silver on animals or goods, described and for a stated term, and the term falls due, there is no harm in the buyer selling those goods back to the seller, before or after the term falls due, for some other goods which he takes immediately and does not delay, whatever their value, except food, which is not permitted to be sold until it is received. The buyer may sell those goods to someone other than the one who sold them to him, for gold, silver or goods, which he receives and does not delay, because delay makes it ugly and brings in what is disliked: debt for debt. ¹

Belongs to the Muwatta, Book of Sales. Source: the Muwatta. Mentions Malik ibn Anas. Built on in the chapters on advance purchase (salaf) and riba.