Sahih Muslim 1143
Sahih Muslim · Book 13: The Book of Fasting · It is disliked to single out Friday for fasting, unless it coincides with a day that one customarily fasts
وَحَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ ، أَخْبَرَنَا ابْنُ جُرَيْجٍ ، أَخْبَرَنِي عَبْدُ الْحَمِيدِ، بْنُ جُبَيْرِ بْنِ شَيْبَةَ أَنَّهُ أَخْبَرَهُ مُحَمَّدُ بْنُ عَبَّادِ بْنِ جَعْفَرٍ ، أَنَّهُ سَأَلَ جَابِرَ بْنَ عَبْدِ اللَّهِ - رضى الله عنهما - بِمِثْلِهِ عَنِ النَّبِيِّ صلى الله عليه وسلم .
Muhammad b. 'Abbas b. Ja'far reported that he asked Jabir b. Abdullah (Allah be pleased with them), whether he had heard like this from the Messenger of Allah (ﷺ).