1760/1 - Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah’s peace and blessings be upon him) said: “Do not single out the night of Friday for performing voluntary night prayer and do not single out the day of Friday for fasting, unless it is part of the ongoing regular fast of anyone of you.” [Narrated by Muslim]
1761/2 - He also reported that he heard the Prophet (may Allah’s peace and blessings be upon him) say: “None of you should fast on Friday, unless he fasts a day before it or a day after it.” [Narrated by Al-Bukhāri and Muslim]
1762/3 - Muhammad ibn ‘Abbād reported: “I asked Jābir (may Allah be pleased with him): ‘Did the Prophet (may Allah’s peace and blessings be upon him) prohibit fasting on Friday?’ He replied in the affirmative.” [Narrated by Al-Bukhāri and Muslim]
1763/4 - Mother of the Believers Juwayriyah bint al-Hārith (may Allah be pleased with her) reported that the Prophet (may Allah’s peace and blessings be upon him) went to her on Friday while she was fasting and asked: “Did you fast yesterday?” She replied in the negative. He said: “Do you intend to fast tomorrow?” She replied in the negative. Thereupon, he said: “Then, break your fast.” [Narrated by Al-Bukhāri]
1) It is prohibited to single out Friday alone for fasting. But it is permissible to fast it along with a day before or a day after.
2) It is not permissible to single out the night of Friday for performing voluntary night prayer, as linking any act of worship to a particular time requires a Shariah proof.
He who performs the voluntary night prayer on a regular basis is not subject to this prohibition. It is permissible for him to perform it on Friday night, for he does not single it out for this worship, and Allah knows best.