Question: Is it permissible to supplicate during the prayer using a supplication from the Qur'an if one adds the phrase 'O Allāh' (اللهم)?

Sheikh Yahya hafidahullah responds: If someone says in their Sujood or rukoo': 'O Allah, grant us good in this world and good in the Hereafter and protect us from the punishment of the Fire.' This is a ḥadīth and not an Āyah. The Āyah says: ربنا 'Our Lord, grant us good in this world...' or if someone says: 'O Allāh, do not let our hearts deviate after You have guided us, and grant us mercy from Yourself. Indeed, You are the Bestower.' This supplication is not an Āyah. The point is that if the Āyah is not recited verbatim but rather interpreted or adapted from the Qur'an, as the Prophet ﷺ did—for example, 'Exalt the name of your Lord and seek forgiveness. Indeed, He is the Accepting of Repentance'—he would say: 'Glory be to You, O Allāh, our Lord, and praise be to You. O Allāh, forgive me.' This type of adaptation is permissible. However, reciting the Qur'an during bowing or prostration is not permissible, as the Prophet ﷺ said in the ḥadīth: 'I have been prohibited from reciting the Qur'ān while bowing or prostrating.'