In the name of Allah, the most Beneficent, the most Merciful.
The words Sadaqallahul Azeem means Allah the Great, has spoken the truth. It is an expression affirming what has been recited. It is correct to say that there are no hadiths in which the Prophet of Allah Sallallahu Alahi Wasalam used such words at the end of a recital of the Holy Quran. However, this has been the practice of many of our pious predecessors. Therefore, if one does recite it neither deeming it to be necessary nor a sunnah, one will be adhering to good etiquette.
In the chapter on the ettiquestes of Quranic recitation, Imam Ghazaali (RA) has written in his Ihyaal Uloom:
“The eighth (etiquette) is that he should say at the beginning of his recital: ‘I seek refuge with Allah, All-Knowing from the accursed Shaitan….’ And he should recite Surah Naas and Surah Fatihaa, and he should say upon completing his recital ‘Allah, Most High has spoken the truth, and the Prophet of Allah Sallallahu Alahi Wasalam has delivered (his message)’. ” (p.389 v.1)
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham