Narrated Abu Huraira (RA): The Messenger of Allah (ﷺ) used to instruct us when we go to sleep we should say:

اَللَّهُمَّ رَبَّ السَّمَوَاتِ السَّبْعِ وَرَبَّ الْأَرْضِ، وَرَبَّ الْعَرْشِ الْعَظِيمِ، رَبَّنَا وَرَبَّ كُلِّ شَيْءٍ، فَالِقَ الْحَبِّ وَالنَّوَى، وَمُنْزِلَ التَّوْرَاةِ وَالْإِنْجِيلِ، وَالْفُرْقَانِ، أَعُوْذُ بِكَ مِنْ شَرِّ كُلِّ شَيْءٍ أَنْتَ آخِذٌ بِنَاصِيَتِهِ اَللَّهُمَّ أَنْتَ الْأَوَّلُ فَلَيْسَ قَبْلَكَ شَيْءٌ، وَأَنْتَ الْآخِرُ فَلَيسَ بَعْدَكَ شَيْءٌ، وَأَنْتَ الظَّاهِرُ فَلَيْسَ فَوْقَكَ شَيْءٌ، وَأَنْتَ الْبَاطِنُ فَلَيْسَ دُونَكَ شَيْءٌ، اِقْضِ عَنَّا الدَّيْنَ وَأَغْنِنَا مِنَ الْفَقْرِ

Allaahumma Rabbas-samaawaatis-sab'i, wa Rabbal-Ardi, wa Rabbal-'Arshil-'Adheem, Rabbanaa wa Rabba kulli shay'in, faaliqal-habbi wannawaa, wa munzilat-Tawraati wal-'Injeeli, wal-Furqaan, 'A'oodhu bika min sharri kulli shay'in 'Anta 'aakhithun binaasiyatihi. Allaahumma 'Antal-'Awwalu falaysa qablaka shay'un, wa 'Antal-'Aakhiru falaysa ba'daka shay'un, wa 'Antadh-Dhaahiru falaysa fawqaka shay'un, wa 'Antal-Baatinu falaysa doonaka shay'un, iqdhi 'annad-dayna wa 'aghninaa minal-faqr

O Allah, Lord of the seven heavens and the exalted throne, our Lord and Lord of all things, Splitter of the seed and the date stone, Revealer of the Towraat, the Injeel and the Furqaan, I take refuge in You from the evil of all things You shall seize by the forelock. O Allah, You are The First so there is nothing before You and You are The Last so there is nothing after You. You are ath-Thaahir so there is nothing above You and You are al-Baatin so there is nothing closer than You. Settle our debt for us and spare us from poverty.

Reference: Muslim: 2713, Sahih. Tirmidhi: 3481