Sahih Al Bukhari Hadith Number 1949

Narrated Nafi`: Ibn `Umar recited the verse: “They had a choice either to fast or to feed a poor person for every day, and said that the order of this Verse was canceled.

30  Fasting
Hadith number 1949
Volume no 3
Chapter: 39 (Those who can fast with difficulty have to feed a poor person)