It wasnarrated that Ibn 'Abbas said:
"When praying at night(Qiyamul-Lail), the Messenger of Allah (ﷺ) used to say between thetwo prostrations: 'Rabbighfir li warhamni wajburni warzuqniwarfa'ni(O Lord, forgive me, have mercy on me, improve mysituation, grant meprovision and raise me in status).'" (ES)
English reference (ES): Vol. 1, Book 5, Hadith 898 (ES)
Arabic reference (ES): Book 5, Hadith 948 (ES)