Al-Lu'lu Wal-Marjan 966 — The Book of Sales (Bargains)

[1] (Chap.1) The sale by Mulâmasa has different forms: The sale becomes valid on buyer's touching the clothes without checking or looking at them. For example, one brings a folded garment in the dark and the buyer offers a price and the owner of the garment says, "I sell it to you on condition that you will only touch it, not see it, and if you see it, you have no option to cancel the sale."[2] (Chap.1) The sale by Munâbadah is like gambling: Two persons may agree to barter one thing for another without seeing or checking either of them. One may say to another, "I barter my garment for your garment," and the sale is achieved without either of them seeing the garment of the other. Or one may say, "I give you what I have and you give me what you have," and thus they buy from each other without knowing how much each has had.