باب كَرَاهِيَةِ صِيَامِ يَوْمِ الْجُمُعَةِ مُنْفَرِدًاChapter: It is disliked to single out Friday for fasting, unless it coincides with a day that one customarily fasts
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).