Reference: ad-Durar an-Naadhirah fil-Fataawa al-Mu’aasirah – Page 80
ad-Da’wah 1547 – Safar 1417
Question: What is the ruling regarding saying “sada-qAllaahul-‘Adtheem” after finishing reading the Qur.aan? We have heard many scholars saying this and [have] also heard it [said] on television and radio.
Response: There is no basis nor [Sharee’ah-based] evidence to [suggest] adhering to [saying] this phrase “sada-qAllaahul-‘Adtheem” after finishing reading the Qur.aan, so doing so on a regular basis is an innovation. And the etiquette of reciting [the Qur.aan] is mentioned in books specifically related [to this subject] such as: “Ahkaam al-Qur.aan” of Ibn Katheer, and “at-Tibyaan fee Aadaab Hamlatil-Qur.aan” of an-Noodee and nothing of this sort (i.e. the saying of “sada-qAllaahul-‘Adtheem”) has been mentioned therein, and Allaah [alone] has the Complete knowledge [of all affairs].