509 – Sahl ibn Abi Hathmah (may Allah be pleased with him) said: “The Messenger of Allah, peace and blessings be upon him, instructed us: When you estimate the crop, then take (the due zakat) and leave one-third; if you will not leave one-third, then leave one-quarter.” It was narrated by the Five compilers of the Sunan except Ibn Majah, and Ibn Hibban and al-Hakim declared it sound. ⦗1⦘

Grade of the hadith:
Al-Hakim and Ibn Hibban judged the report authentic. In at-Talkhis it is recorded that Ahmad, the three authors of the Sunan, Ibn Hibban, and al-Hakim transmitted it from Ibn Abi Hathmah. In its chain appears ‘Abd al-Rahman ibn Mas‘ud ibn Niyar, the narrator from Sahl; al-Bazzar remarked that he is the sole transmitter of it, while Ibn al-Qattan said his reliability is unknown. Al-Hakim added that the hadith has a corroborating chain whose authenticity is agreed upon, in which ‘Umar ibn al-Khattab issued the same directive.

Vocabulary of the hadith:
• “When you estimate (idha kharastum)”: addressed to the zakat collectors and field agents.
• kharastum: with an open kha and an open ra followed by a still sad; it follows the pattern of nasara/yanṣuru and ḍaraba/yaḍribu. It denotes assessing something—estimating it by conjecture and approximation. People say: “He assessed the palm-trees and vines,” meaning he calculated how many dried dates would come from their fresh fruit and how many raisins from their grapes.
In the phrase idha kharastum, idha is a conditional particle, kharastum is the condition, and its answer is fakhudhū (“then take”), with wadha‘ū (“and leave”) conjoined to it.
• “Leave one-third (da‘ū ath-thuluth)”: i.e., leave for the owner of the wealth one-third of the amount you have estimated.