Sunan Abi Dawud Book 2, Hadith 376
Asim ibn Humayd said: I asked Aisha: By what words the Messenger of Allah (ﷺ) would begin his supererogatory prayer at night?
She replied: You ask me about a thing of which no one asked me before you. When he stood up, be uttered the takbir (Allah is most great) ten times, and uttered "Praise be to Allah" ten times, and uttered "Glory be to Allah " ten times, and uttered "There is no god but Allah" ten times, and sought forgiveness ten times, and said: O Allah, forgive me, and guide me, and give me sustenance, and keep me well, and he sought refuge in Allah from the hardship of standing before Allah on the Day of Judgment.
Abu Dawud said: This tradition has also been narrated by Khalid b. Ma'dan from Rab'iah al-Jarashi on the authority of 'Aishah.
I head the Prophet(ﷺ) uttering (all these supplications) in a supererogatory prayer; he narrated the tradition in a similar manner.
I asked ‘A’ishah: By what words the Prophet(ﷺ) used to begin his prayer when he stood up at night (to offer tahajjud prayer). She said: When he stood up at night, he began his prayer by saying: O Allah, Lord of Jibra’il, Lord of Mik’ail, and Lord of Israfil, Creator of the Heavens and the Earth, the Knower of what is seen and of what is unseen; Thou decides between Thy servants in which they used to differ. Guide me to the truth where there is a difference of opinion by Thy permission. Thou guidest anyone Thou wishes to the right path.