throws a shorter distance. Conditions also vary according to the wind: it may be a headwind, a crosswind, or a tailwind, and this makes a difference. Thus, sale by pebble is prohibited and invalid, because it involves excessive uncertainty, and the Prophet, may Allah’s peace and blessings be upon him, prohibited sales involving excessive uncertainty (1).

Question: In some shops, everything is five riyals, or everything is ten riyals. Does this fall under the same category?

Answer: No, because the buyer will only purchase after knowing what he wants. He says, “I take the bag, I take the book, I take the pen, I take the watch for ten.” Thus, everything is known.

Question: If someone brings a carton containing garments, caps, cloaks, and sandals, all mixed together, and says, “I sell you this carton, each item in it for one dirham,” this is invalid because it is unknown. But if he says, “It contains ten pairs of sandals, ten caps, ten garments, and ten cloaks, and each one is such-and-such,” then this is valid, because it is known, though it requires calculation. However, if the quantity of each type is unknown, then this is invalid.

His statement, “nor one slave from among his slaves and the like”: that is, it is not valid for him to sell one slave from among his slaves, because of the lack of specification. The item sold must be specified; if it is not specified, the sale is invalid. For example, a man may own one hundred slaves—and this did occur. Al-Zubayr, may Allah be pleased with him, owned one thousand slaves, and he contracted them to pay him a dirham each day,