If someone were to ask: Why did the scholars base the measure on weight, when the sunnah specifies it by volume?

The answer is that weight is more reliable, because sāʿs and mudds vary from one time to another and from one place to another. It was therefore converted to weight, since weight is determined by mithqāls, which have remained constant from the earliest period of Islam until today. This is more dependable and makes the standard easy to determine.

Our shaykhs mentioned that the Prophet’s sāʿ is four mudds, as established by the sunnah, whereas the sāʿ used by us is three mudds, despite being larger than the Prophet’s sāʿ. This shows that, if we were to rely on volume, considerable variation would result.

In terms of weight, the Prophetic sāʿ is equivalent to 2.040 kilograms of wheat. Thus, one may take a vessel, place in it the wheat that has been weighed, and, once it is full, that is the Prophetic sāʿ. We have a copper sāʿ which we found among ruins in ʿUnayzah. Engraved on its exterior are the words: “This belongs to so-and-so, from so-and-so, from so-and-so,” until its chain reaches Zayd ibn Thābit. I tested it by weight: I brought firm, high-quality wheat, filled this vessel, and weighed it, and found it to be close to what the jurists mentioned.

“The produce of a single year is to be combined with itself in completing the nisab, but one category is not combined with another . . .”

His statement, “The produce of a single year is to be combined with itself in completing the nisab, but one category is not combined with another,” means that if a person has an orchard, part of which is harvested early while another part ripens later, we combine one part with the other until the nisab is completed. Thus, if the first is half a nisab and the second