كتاب التفسير
65  
Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
(26)
"So whoever of you sights (the crescent on the first night of) the month (of Ramadan, i.e., is present at his home), he must observe Saum (fast) that month... (V.2:185)
(26)
Sahih al-Bukhari 4506

Narrated Nafi`:

Ibn `Umar recited: "They had a choice, either fast or feed a poor for every day.." and added, "This Verse is abrogated."

حَدَّثَنَا عَيَّاشُ بْنُ الْوَلِيدِ، حَدَّثَنَا عَبْدُ الأَعْلَى، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّهُ قَرَأَ ‏{‏فِدْيَةٌ طَعَامُ مَسَاكِينَ‏}‏ قَالَ هِيَ مَنْسُوخَةٌ‏.‏
Reference : Sahih al-Bukhari 4506
In-book reference : Book 65, Hadith 33
USC-MSA web (English) reference : Vol. 6, Book 60, Hadith 33
  (deprecated numbering scheme)