رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1761
The Book of the Prohibited actions
Abomination of Selecting Friday for Fasting
وَعَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: لَا يَصُومَنَّ أَحَدُكُمْ يَوْمَ الْجُمُعَةِ إِلاَّ يَوْمًا قَبْلَهُ أَوْ بَعْدَهُ ((مُتَّفَقٌ عَلَيْهِ)).
Abu Hurairah (May Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) as saying: "None of you should observe fast on Friday except that he should observe fast either one day before it or one day after it." [Al-Bukhari and Muslim].
Riyad as-Salihin, 1761