Allāhumma innī as'aluka yā Allāh
bi'annaka ‘l-Wāḥidu ‘l-Aḥaduṣ-ṣamad,
alladhī lam yalid wa lam yūlad,
wa lam yakun lahu kufuwan aḥad,
an taghfir lī dhunūbī,
innaka anta ‘l-Ghafūrur-Raḥīm.
O Allah, I ask You. O Allah, You are the One, the Only, Self-Sufficient Master, Who was not begotten and begets not, and none is equal to Him.
Forgive me my sins, surely you are Forgiving, Merciful.
Reference:
An-Nasa'i 3/52, Ahmad 4/338. See also Al-Albani, Sahih An-Nasa'i 1/280 and
Sifat Salatun-Nabi, pg. 204.