(12) باب صَلاَةِ الضُّحَى
Abu al-Aswad al-Dailani said:
While we were present with Abu Dharr, he said: In the morning, alms are due for him, ever fast is alms, every pilgrimage is alms, every utterance of "Glory to be Allah" is alms, every utterance of "Allah is most great" is alms, every utterance of "Praise be to Allah" is alms. The Messenger of Allah (ﷺ) recounted all such good works. He then said: Two rak'ahs which one prays in the Duha serve instead of that.
Reference: Sunan Abi Dawud 1286
In-book reference: Book 5, Hadith 37
English translation: Book 5, Hadith 1281