Abu Dawud Book 2, Hadith Number 1281.
Chapter : Prayer in the forenoon.
Narated By Abu al-Aswad al-Dailani : When we were present with Abu Dharr, he said: in the morning alms are due from every bone on a man’s fingers and toes. Every prayer is alms for him; every fast is an alm; every pilgrimage is alms; every utterance og “Glory be to Allah” is alms; every utterance of “Allah is most great” is alms; every utterance of “Praise be to Allah” is alms. The Apostle of Allah (PBUH) recounted all such good works. He then said: Two rak’ahs which one prays in the forenoon serve instead of that.