That the Messenger of Allah told 'Attab bin Usaid to estimate the (harvest of) grapes, and to pay Zakah in raisins, just as the Zakah on date palms is given in died dates.
Sunan an-Nasa'i Book 23, Hadith 184
← Previous Hadith 'Umar give a house in charity for the sake of Allah, the Mighty and Sublime, and he found it being offered for sale after that. He wanted to buy it, then he went to the Messenger of Allah and asked him about that. The Messenger of Allah said: "Do not take back what you have given in charity."

Sunan an-Nasa'i Book 23, Hadith 183 Next Hadith → "The Messenger of Allah addressed the people and said: 'Allah, the Mighty and Sublime, has enjoined upon you Hajj.' A man said: 'Every year?' He remained silent until he had repeated it three times. Then he said: 'If I said yes, it would be obligatory, and if it were obligatory you would not be able to do it. Leave me alone so long as I have left you alone. Those who came before you were destroyed because they asked too many questions and differed with their prophets. If I command you to do something then follow it as much as you can, and if I forbid you to do something then avoid it."'

Sunan an-Nasa'i Book 24, Hadith 1