Sahih Bukhari Volume 2, Book 21, Hadith Number 221.
Narated By Ibn Abbas : When the Prophet got up at night to offer the Tahajjud prayer, he used to say: Allahumma lakal-hamd. Anta qaiyimus-samawati wal-ard wa man fihinna. Walakal-hamd, Laka mulkus-samawati wal-ard wa man fihinna. Walakal-hamd, anta nurus-samawati wal-ard.…