(2) باب نَسْخِ قَوْلِهِ { وَعَلَى الَّذِينَ يُطِيقُونَهُ فِدْيَةٌ }
Ibn 'Abbas explain the Qur'anic verse "For those who can do it(with hardship) is a ransom, the feeding of one, that is indigent" said "If one of them wished to pay ransom by providing food to an indigent person he could pay ransom.. Thus, his fast was complete. Allaah, the Exalted pronounced "But he that will give more of his own free will, it is better for him". Again he pronounced "So every one of you who is present (at his home) during that month should spend it in fasting." But, if anyone is ill or on a journey the prescribed period (should be made up) by days later.
Reference: Sunan Abi Dawud 2316
In-book reference: Book 14, Hadith 4
English translation: Book 13, Hadith 2309