It wasnarrated that 'Abdullah bin Ma'qil said:
"I sat with Ka'b bin'Ujrah in the mosque and asked him about this Verse: 'He must payacompensation of either fasting (three days) or giving charity(feedingsix poor persons) or offering sacrifice (one sheep).'[2:196] Ka'bsaid: it was revealed concerning me. I had troublewith my head, so Iwas carried to the Messenger of Allah (ﷺ), withlice crawling on myface. He said: 'I did not think that you weresuffering as much as Isee. Do you have a sheep?' I said: 'No.'Then this Verse was revealed:"He must pay a Fidyah (ransom) ofeither fasting (three days) orgiving Sadaqah (charity – feedingsix poor persons) or offeringsacrifice (one sheep)." [2:196] Hesaid: 'Fasting is three days,charity is to be given to six poorpersons, giving each one half of aSa' of food, and the sacrificeis a sheep.'"
English reference: Vol. 4, Book 25, Hadith 3079
Arabic reference: Book 25, Hadith 3197