I just got told by a friend that by reciting Surah al-Qadr the sins of 40 years will be forgiven? Also it should be read after the completion of wudoo (ablution)? I am aware that we should recite bismillah before starting wudoo and after finishing it we should recite the kalimah shahadat (testimony of faith).

Please clear away this doubt for me since I am not sure if any of this is backed by authentic hadeeth or not.

Praise be to Allah

There is no shar‘i (religious) basis for this idea, and there
is nothing in the Sunnah (teachings) of the Prophet (peace and blessings of
Allah be upon him) to suggest this. 

Al-Sakhkhawi (may Allah have mercy on him) said: Reciting the
Surah “Inna anzalnahu” [i.e., Surah al-Qadr] after finishing wudoo is
something for which there is no basis and this is not the Sunnah. End
quote. 

Al-‘Amiri al-Ghazzi (may Allah have mercy on him) said: 

Reciting Surah al-Qadr after finishing wudoo is something for
which there is no basis. 

Al-Jadd al-Hatheeth fi Bayan ma laysa bi Hadeeth (p.234). 

Al-Albani (may Allah have mercy on him) mentioned in
al-Da‘eefah (1449) a hadeeth (narration) about this and he said concerning
it: It is fabricated (mawdoo‘). 

There are proven du‘as and athkar (words of remembrance) in
the Prophet’s (peace and blessings of Allah be upon him) Sunnah which may be
recited straight after doing wudoo. The Muslim should be keen to recite them
and not add anything to them. 

For more information please see the answer to question no.


45730

And Allah knows best.