(63) بَابُ صَوْمِ يَوْمِ الْجُمُعَةِ، فَإِذَا أَصْبَحَ صَائِمًا يَوْمَ الْجُمُعَةِ فَعَلَيْهِ أَنْ يُفْطِرَ
Narrated Abu Aiyub from Juwairiya bint Al-Harith:
The Prophet (ﷺ) visited her (Juwairiya) on a Friday and she was fasting. He asked her, "Did you fast yesterday?" She said, "No." He said, "Do you intend to fast tomorrow?" She said, "No." He said, "Then break your fast." Through another series of narrators, Abu Aiyub is reported to have said, "He ordered her and she broke her fast."
Reference: Sahih al-Bukhari 1986
In-book reference: Book 30, Hadith 93
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 31, Hadith 207