A fabricated hadeeth about the virtue of praying qiyaam al-layl on Saturday night
This hadeeth is fabricated. It was quoted by al-Shawkaani (may Allaah have mercy on him) in al-Fawaa’id al-Majmoo’ah fi’l-Ahaadeeth al-Mawdoo’ah (p. 44), as quoted in the question. He said: It was narrated by al-Jawzaqaani from Anas in a marfoo’ report (i.e. attributed to the Prophet (peace and blessings of Allaah be upon him)). But it is mawdoo’ (fabricated), and the men of its isnaad are either majhool (unknown) or matrook (rejected).
Prayer at night is mustahabb on all days, and is not restricted to what is mentioned in this fabricated hadeeth.
Allaah says (interpretation of the meaning):
“Their sides forsake their beds, to invoke their Lord in fear and hope, and they spend (in charity in Allaah’s Cause) out of what We have bestowed on them.
No person knows what is kept hidden for them of joy as a reward for what they used to do”
“Verily, the Muttaqoon (the pious) will be in the midst of Gardens and Springs (in the Paradise),
Taking joy in the things which their Lord has given them. Verily, they were before this Muhsinoon (good-doers).
They used to sleep but little by night [invoking their Lord (Allaah) and praying, with fear and hope].
And in the hours before dawn, they were (found) asking (Allaah) for forgiveness”
Al-Tirmidhi (3549) narrated from Abu Umaamah that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “I urge you to pray qiyaam al-layl, because that was the habit of the righteous who came before you; it will bring you closer to your Lord, expiate for bad deeds and keep you away from sin.”
Classed as hasan by al-Albaani in Irwa’ al-Ghaleel, 452.
And Allaah knows best.