Question Summary:
The Ahl al – Hadeeth say that to recite “Ya Qawiyyu” is found in which Hadeeth?

Question Detail:

The Ahl al – Hadeeth say that to recite “Ya Qawiyyu” is found in which Hadeeth?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu `alaykumwa-rahmatullāhiwa-barakātuh. 
You are probably referring to the practice of placing the hand on the forehead after Fardh Salaah and reading Ya Qawiyyu.
If so, then such a practice is classified as Mubaah. Mubaah refers to an act that is permissible.[1] 
Qawiyyu is an attribute of Allah (Subhanahu Wa Ta’ala). By placing one’s hand on the forehead and taking the name of Allah (Subahnahu Wa Ta’ala), one intends to invoke the help and blessing of Allah (Subhanahu Wa Ta’ala) for a specific issue. In this case it is for good memory which is tried and tested by others.
Many people have placed their hand on the forehead and recited Ya Qawiyyu and observed benefit in doing so. 
It is sufficient that Shariah did not prohibit emulating such a practice. Therefore, one may follow a tried and tested practice on condition one does not regard it to be compulsory.
This is similar to emulating some diet or medicine that has been proven to be beneficial. Nobody regards that as Bid’ah[2] as long as one does not regard the practice to be compulsory. 
To object to something that is Mubaah (permissible) without any Shar’ee motivation is incorrect.
However, the ideal is to make Du’aa the Sunnah way and beseech Allah (Subhanahu Wa Ta’ala) to fulfill our needs.
And Allah knows best. 
Ismail Desai
Durban, South Africa
Student DarulIftaa
Checked and Approved 
Mufti Ebrahim Desai
Daaruliftaa.net