Abu Dharr (May Allah be pleased with him) reported:
The Prophet (PBUH) said,
"In the morning, charity is due on every joint bone of the body of everyone of you.
Every utterance of Allah's Glorification (i.e., saying Subhan Allah) is an act of charity, and every utterance of His Praise (i.e., saying Al-hamdu lillah) is an act of charity and every utterance of declaration of His Greatness (i.e., saying La ilaha illAllah) is an act of charity; and enjoining M`aruf (good) is an act of charity, and forbidding Munkar (evil) is an act of charity, and two Rak`ah Duha prayers which one performs in the forenoon is equal to all this (in reward).''
(Imam Muslim)