حَدَّثَنِي يَحْيَى ، عَنْ مَالِك ، أَنَّهُ بَلَغَهُ ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ ، أَنَّهُ سُئِلَ عَنْ رَجُلٍ نَذَرَ صِيَامَ شَهْرٍ هَلْ لَهُ أَنْ يَتَطَوَّعَ ، فَقَالَ سَعِيدٌ : " لِيَبْدَأْ بِالنَّذْرِ قَبْلَ أَنْ يَتَطَوَّعَ "
Sa'id ibn al-Musayyib was asked about a person who made a vow to fast for a month. Is it permissible for him to observe voluntary fasts? He replied: He should first fulfill the vowed fasts, then observe voluntary fasts.