The ahaadeeth about the virtue of praying qiyaam all the nights of the week are false
Question

                I got a letter which contained ahaadeeth from the Messenger (peace and blessings of Allaah be upon him) which spoke of the virtue of praying at night, and it was the first time in my life that I had ever heard these ahaadeeth. I hope that you can explain to me whether these ahaadeeth are saheeh or not. 

It was narrated that Anas ibn Maalik (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: 

Whoever prays two rak’ahs on the night before Friday, reciting in each rak’ah the Opening of the Book (al-Faatihah) and Soorat al-Zalzalah fifteen times, and when he finishes his prayer he says “Ya Hayyu ya Qayyoom Ya Dha’l-jalaali wa’l-ikraam (O Ever-Living, O Self-Sustaining, possessor of majesty and honour)” 100 times, Allaah will keep him safe from the torment, darkness and constriction of the grave and the terrors of the Day of Resurrection, and he will not get up from his place either hungry or thirsty, and he will be clothed with a suit of light, and he will not depart from this world until he has seen his place in Paradise.

The second hadeeth is: 

It was narrated from Mu’aadh ibn Jabal (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said:  

“Whoever prays on the night before Saturday 16 rak’ahs, reciting in each rak’ah al-Faatihah and Soorat al-Ikhlaas 31 times, evil, whispers (waswaas), self-admiration and showing off will be expelled from his heart and Allaah will fill his heart with light, mercy and kindness, and on the Day of Resurrection He will clothe him in forgiveness and his face will remain like the moon when it is full, and for every rak’ah He will build a palace for him in Paradise.  

And there are other ahaadeeth which were narrated from the Messenger (peace and blessings of Allaah be upon him). 

I hope that you can tell me whether I should offer these prayers or not; are these ahaadeeth saheeh or da’eef?.
Praise be to Allah.
    There is no saheeh hadeeth which singles out any day or night 
    of the week for praying qiyaam or offering naafil prayers. Everything that 
    has been narrated concerning that is false and is a fabrication against the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him), and it 
    is not permissible to narrate it, let alone act upon it. The one who acts 
    upon such false ahaadeeth is introducing an innovation into the religion 
    that is not a part of it, so he should beware of the wrath and punishment of 
    Allaah. 

    Shaykh al-Islam Ibn Taymiyah (may Allaah be pleased with him) 
    said in Majmoo’ al-Fataawa (23/134): 

    With regard to prayers on Sunday and Monday and other days of 
    the week – even though it is mentioned by some of those who wrote about 
    raqaa’iq (heart softeners) – there is no difference of opinion among the 
    scholars of hadeeth that all of these ahaadeeth are fabricated and none of 
    the imams regarded these prayers as mustahabb. In Saheeh Muslim it is 
    narrated from Abu Hurayrah (may Allaah be pleased with him) that the Prophet 
     (peace and blessings of Allaah be upon him) said: “Do not single out 
    the night before Friday for praying or the day of Friday for fasting.” And 
    Allaah knows best. End quote. 

    Ibn al-Qayyim aid in al-Manaar al-Muneef (95): 

    The ahaadeeth about praying on certain days or nights, such 
    as praying on Sunday or the night before Sunday, or on Monday or the night 
    before Monday, and other days of the week, are all false ahaadeeth. End 
    quote. 

    Al-‘Iraaqi (may Allaah have mercy on him) said in Takhreej 
    al-Ihya’ (1/259): 

    There is no saheeh hadeeth about the days or nights of the 
    week, all of the reports are da’eef (weak) and false. End quote.  

    Al-Shawkaani said in al-Fawaa’id al-Majmoo’ah (46): 

    It says in al-Mukhtasar: There is no saheeh report 
    about the prayers during the week. End quote. 

    There are verses and saheeh ahaadeeth which speak of the 
    virtue of praying qiyaam al-layl in general terms. Please see the answer to 
    question no. 50070. 

    And Allaah knows best.