وعن أم سلمة رضي الله عنها أن رسول الله صلى الله عليه وآله وسلم أكثر ما كان يصوم من الأيام يوم السبت ويوم الأحد . وكان يقول : « إنهما يوما عيد للمشركين وأنا أريد أن أخالفهم ». أخرجه النسائي وصححه ابن خزيمة وهذا اللفظ له.
Umm Salamah (RAA) narrated, The Messenger of Allah (ﷺ) used to fast more often on Saturdays and Sundays than on the other days. He would say, "They are the 'ids of the polytheists, and I love to act contrary to what they do." Related by An-Nasal and was rendered authentic by Ibn Khuzaimah, and the wording is his.
Explanation & Benefits
Shaykh Safi ur-Rahman Mubarakpuri
565 Benefit:
From the first hadith, it appears that the Messenger of Allah (sallallahu alayhi wa sallam) forbade fasting on Saturday. However, that narration is disturbed (mudtarib) and abrogated, as the author of the Musannaf has mentioned, and its abrogating narration is precisely this hadith of Umm Salamah (radi Allahu anha), that the Messenger of Allah (sallallahu alayhi wa sallam) would generally fast on Saturdays and Sundays, solely for the purpose of opposing the Jews and Christians, because the Jews venerate Saturday and the Christians venerate Sunday. By fasting on both of these days in contrast to them, he made it clear that these are not days of Eid or veneration, because it is prohibited to fast on the days of Eid. *
Source: Bulugh al-Maram: Commentary by Safiur Rahman Mubarakpuri, Page: 565