574 – Abū Hurayrah (may Allah be pleased with him) reported that the Prophet (peace and blessings be upon him) said: “Do not single out the night of Friday for voluntary night worship over the other nights, and do not single out the day of Friday for fasting over the other days, unless it happens to fall within a fast one of you is already observing.” Reported by Muslim (1).

575 – Abū Hurayrah (may Allah be pleased with him) also reported that the Messenger of Allah (peace and blessings be upon him) said: “None of you is to fast on Friday unless he fasts a day before it or a day after it.” Agreed upon (2).

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Glossary of the hadith:
• lā takhussū: do not set it apart from the other days and nights.

Points derived from the two hadiths:

1. Friday is the best day of the week. Abū Dāwūd (883) narrates that the Prophet (peace and blessings be upon him) said, “The best of your days is Friday.” Al-Bukhārī (847) and Muslim (1412) likewise record that he said, “The sun has never risen nor set on a day better than Friday; Allah guided us to it, while other people were led away from it.”
   Thus Friday is the Muslims’ weekly festival, and their gathering on that day is the finest of all gatherings except the standing at ʿArafah. For this reason fasting on it is discouraged: it is a day of adornment and joy in which the Muslim displays the honor, strength, and vigor of Islam and performs its rites with energy and resolve.