Sahih al-Bukhari 1917
Book 30: Fasting · Hadith 27
Hadith text
Narrated Sahl bin Sa`d:When the following verses were revealed: 'Eat and drink until the white thread appears to you, distinct from the black thread' and of dawn was not revealed, some people who intended to fast, tied black and white threads to their legs and went on eating till they differentiated between the two. Allah then revealed the words, 'of dawn', and it became clear that meant night and day
Sahl bin Sa'd bataate hain: Jab yeh ayaat nazil hui: "Khao-piyo jab tak tumhe safed dhaaga kaale dhaage se saaf alag dikhe" aur 'subah ka' hissa nazil nahi hua tha, kuch log jo roza rakhna chahte the, apni taangon mein kaale-safed dhaage baandh lete aur khate rahte jab tak woh dono mein farq na kar lete. Allah ne phir "subah ka" alfaaz nazil kiye, aur saaf ho gaya ke iska matlab raat aur din tha.
Sahih al-Bukhari 1917 · Book 30, Hadith 27