سنن النسائي

It was narrated that Ibn Umar said: "While we were praying with the Messenger of Allah (ﷺ), a man among the people said: 'Allahu Akbaru kabira, wal-hamdu Lillahi kathira, wa subhan-Allahi bukratan was asila (Allah is Most Great and much praise be to Allah and glorified be Allah at the beginning and end of the day).' The Messenger of Allah (ﷺ) said: 'Who is the one who said such and such?' A man among the people said: 'I did, O Messenger of Allah.' He said: ' I like it,' and he said words to the effect that the gates of the Heavens had been opened for it." Ibn Umar said: "I never stopped saying it since I heard the Messenger of Allah (ﷺ) say that."