Whenever the Prophet (ﷺ) got up at night to offer the Tahajjud prayer he used to say:

"Allahumma lakal-ḥamd. Anta Qaiyimus-samâwâti wal-ard wa man fihinna. Wa lakal-ḥamdu, Anta Nur us-samâwâti wal-ard wa man fîhinna. Wa lakal-ḥamd, Anta Malikus-samâwâti wal-ard wa man fihinna. Wa lakal- ḥamd, Antal-Haq wa wa‘dukal-haq, wa liqâ'uka, wa qauluka, wal-jannatu haq wan-naru wannabi-yûna haq, wa Muḥammadun haq, was-sâ'atu haq. Allâhumma laka as-lamtu wabika âmantu, wa'alaika tawakkaltu, wa ilaika anabtu wa bika khâṣamtu, wa ilaika hâkamtu faghfir li ma qaddamtu wa ma akh-khartu wa ma as-rartu wa alantu, Antal- Muqaddim wa Antal-Muakhkhir, La ilâha illa Anta (or La ilâha ghairuka).

[O Allah ! All the praises are for You; You are the Holder of the heavens and the earth, and whatever is in them. All the praises are for You; You are the Light of the heavens and the earth; and whatever is in them, You are the King of the heavens and the earth; and whatever is in them, and all the praises are for You; You are the Truth and Your Promise is the truth; and the Meeting with You is the truth; Your Words are the truth; and Paradise is the truth; and Hell is the truth and all the Prophet's (peace be upon them) are the truth. And Muḥammad (ﷺ) is the truth; and the Hour (Day of Resurrection) is the truth. O Allah ! I surrender to You, I believe in You and depend on You, and repent to You, and with Your Help I argue (with my opponents, the disbelievers), and I take You as a Judge (to judge between us). Please forgive me my past and future sins; and whatever I concealed and whatever I revealed; and You are the One Who makes (some people) forward and (some) backward; there is none who has the right to be worshipped but You (or, there is no other deity than You)].

[Sufyân said that Abdul Karîm Umaiyya added to the above, Wa ḥaula wa quwata illâ billâh (There is neither might nor power except with Allah)]. [2:221-O.B.]