(It should be noted that the night of Friday is Thursday night as we know it in the west)
According to another traditional report, this one transmitted on the authority of Jabir ibn 'Abdi 'llah [al-Ansari] (may Allah be well pleased with him and with his father) the Prophet (Allah bless him and give him peace) once said:
If someone performs twelve [voluntary] cycles of ritual prayer [ithnatai 'asharata rak'a] on a Friday night, at some point between the [obligatory prayers of] sunset [al-maghrib] and late evening [al-'isha']--reciting in each cycle the Opening Sura of the Book [Fatihat al-Kitab], and "Qul Huwa'llahu Ahad [Say: 'He is Allah, One!']" ten times--it will be as if he had devoted himself to the worshipful service of Allah (Exalted is He) for twelve whole years, by fasting every day and keeping vigil every night throughout that time.
According to yet another traditional report, this one transmitted on the authority of Kathir ibn Salama, Anas ibn Malik (may Allah be well pleased with him) stated that Allah's Messenger (Allah bless him and give him peace) once said:
If, on a Friday night, someone performs the [obligatory] late evening ritual prayer [salat al-'isha' al-akhira] in a congregation [jama'a], and follows it with the performance of the two cycles of customary prayer [rak'atayi 's-sunna], then goes on to perform ten cycles [of additional, voluntary] prayer-reciting in each cycle "Al-hamdu li'llahi... [Praise be to Allah...']" one time, "Qul Huwa'llahu Ahad [Say: 'He is Allah, One!']" one time, and the Two Pleas for Divine Refuge [al-Mu'awwidhatain] one time each--and if he then performs a witr prayer of three cycles, and sleeps on his right side, with his face turned toward the Qibla [the direction of the Ka'ba in Mecca] --it will be as if he had kept vigil throughout the Night of Power [Lailat al-Qadr].
The Prophet (Allah bless him and give him peace) also said:
Invoke Allah's blessing upon me, many times over, in the course of the illustrious night [al-lailat al-gharra'], and during the brightly shining day [al-yawm al-azhar]--on the night of Friday, the Day of Congregational Prayer [Lailat al-Jum'a], and then on the Day itself.
