(63) بَابُ صَوْمِ يَوْمِ الْجُمُعَةِ، فَإِذَا أَصْبَحَ صَائِمًا يَوْمَ الْجُمُعَةِ فَعَلَيْهِ أَنْ يُفْطِرَ
Narrated Muhammad bin `Abbas:
I asked Jabir "Did the Prophet (ﷺ) forbid fasting on Fridays?" He replied, "Yes." (Other narrators added, "If he intends to fast only that day.") (ID)
Reference (ID): Sahih al-Bukhari 1984 (ID)
In-book reference (ID): Book 30, Hadith 91 (ID)
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 31, Hadith 205 (ID)