Abu Dharr reported,

The Prophet ﷺ said, "Each morning, charity is due upon every joint of one of you. Every utterance of 'Glory be to Allah' is a charity, every utterance of 'Praise be to Allah' is a charity, every utterance of 'There is no god but Allah' is a charity, and every utterance of 'Allah is the Greatest' is a charity. Enjoining what is right is a charity, and forbidding what is wrong is a charity. All of this can be fulfilled by two units of prayer offered in the forenoon."

Muslim 1671

Sahih

حدثنا عبد الله بن محمد بن أسماء الضبعي حدثنا مهدي وهو ابن ميمون حدثنا واصل مولى أبي عيينة عن يحيى بن عقيل عن يحيى بن يعمر عن أبي الأسود الدؤلي

عن أبي ذر

عن النبي ﷺ أنه قال يصبح على كل سلامى من أحدكم صدقة فكل تسبيحة صدقة وكل تحميدة صدقة وكل تهليلة صدقة وكل تكبيرة صدقة وأمر بالمعروف صدقة ونهي عن المنكر صدقة ويجزئ من ذلك ركعتان يركعهما من الضحى

مسلم 1671صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Travelers' prayer and its shortening
Chapter
Recommendation of Duha prayer, that its minimum is two rakahs and its most complete is eight rakahs and its middle is four or six rakahs, and the encouragement to maintain it
Numbering
Darussalam 1671
Muslim 1671