The wording below is commonly found in books of du'a and recited after Qur'an completion
The Scholars generally do not consider it an authentic hadith from the Prophet ﷺ in this full form.
Allāhumma-rḥamnā bil-Qur'ān, wajʿalhulanā imāman wa nūran wa hudan wa raḥmah
"O Allah, have mercy upon us through the Qur'an, and make it for us a leader, a light, a guidance, and a mercy."
The longer version commonly recited
Allāhumma-rḥamnā bil-Qur'ān, wajʿalhu lanā imāman wa nūran wa hudan wa raḥmah. Allāhumma dhakkirnā minhu mā nasīnā, wa ʿallimnā minhu mā jahilnā, warzuqnā tilāwatahu ānā'a al-layli wa aṭrāfa an-nahār, wajʿalhu ḥujjatan lanā yā Rabbal-ʿĀlamīn.
O Allah, have mercy upon us through the Qur'an and make it for us a leader, a light, a guidance, and a mercy. O Allah, remind us of what we have forgotten from it, teach us what we do not know from it, grant us its recitation during the night and the ends of the day, and make it a proof in our favor, O Lord of the worlds.