fasts a day before it or a day after it (1).
This removes the difficulty perceived by those who say that fasting on Saturday is a form of venerating it, and thus accords with the People of the Book in venerating it, even though fasting on it differs from their practice. Such veneration occurs only when Saturday is singled out for fasting. There is no doubt that the hadith does not mention singling it out; fasting on it together with another day does not constitute venerating it. And Allah knows best.
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It was not his practice, may Allah bless him and grant him peace, to fast continuously or to fast every day. Rather, he said: “Whoever fasts every day has neither fasted nor broken his fast” (2). He did not mean someone who fasts on days when fasting is forbidden, for he said this in response to someone who asked: “What about someone who fasts every day?” One would not say of someone who does something forbidden, “He has neither fasted nor broken his fast,” for this implies that his fasting and his not fasting are alike: he is neither rewarded nor punished. This is not the case with someone who undertakes a forbidden fast. Thus, this would not be an appropriate answer to a question about forbidden fasting.
Moreover, according to those who regard fasting every day as recommended, such a person has done both something forbidden and something recommended. In their view, he has fasted on the days when fasting is recommended and committed a forbidden act on the days when fasting is prohibited. In neither case can it be said: “He has neither fasted nor broken his fast.” Applying his statement to this case is therefore a clear error.