Hadith 3968
عَنْ كُرَيْبٍ أَنَّهُ سَمِعَ أُمَّ سَلَمَةَ (زَوْجَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ) رَضِيَ اللَّهُ عَنْهَا تَقُولُ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَصُومُ يَوْمَ السَّبْتِ وَيَوْمَ الْأَحَدِ أَكْثَرَ مِمَّا يَصُومُ مِنَ الْأَيَّامِ وَيَقُولُ: ((إِنَّهُمَا عِيدَا الْمُشْرِكِينَ، فَأَنَا أُحِبُّ أَنْ أُخَالِفَهُمْ))
It is narrated from Sayyida Umm Salama (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) used to fast on Saturdays and Sundays more frequently than on other days on which he would fast. He (peace and blessings be upon him) also said regarding them: "These are the festival days of the polytheists, that is, the Jews and Christians, and I wish to oppose them."