Abu Dharr (May Allah be pleased with him) reported: Some people said to Messenger of Allah (PBUH): “O Messenger of Allah, the rich have taken away (all the) reward. They observe Salat (prayers) as we do; and give Sadaqah (charity) out of their surplus wealth.” Upon this he (the Prophet (PBUH)) said, “Has Allah not prescribed for you (a course) following which you can (also) give Sadaqah? In every declaration of the glorification of Allah (i.e., saying Subhan Allah) there is a Sadaqah, and in every Takbir (i.e., saying Allahu Akbar) is a Sadaqah, and in every celebration of praise (saying Al-hamdu lillah) is a Sadaqah, and in every declaration that He is One (La ilaha illallah) is a Sadaqah, and in enjoining of good is a Sadaqah, and in forbidding evil is a Sadaqah, and in man’s sexual intercourse (with his wife) there is a Sadaqah.” They (the Companions) said: “O Messenger of Allah, is there reward for him who satisfies his sexual need among us?” He said, “You see, if he were to satisfy it with something forbidden, would it not be a sin on his part? Similarly, if he were to satisfy it legally, he should be rewarded”.
This Hadith highlights two important points. Firstly, the enthusiasm of the Companions of the Prophet (PBUH) for surpassing each other in good actions. Secondly, it tells that virtue has a vast meaning in Islam and it includes every action which is done with good intention, provided it does not involve disobedience of Allah. So much so that it covers even natural activities of man which fall in the category of Mubah (that which is permissible and may be omitted without fear of sin) and one is rewarded for them. Not only that, one is rewarded even for abstaining from a sin on the condition that the abstention is for the obedience of Allah. Then abstention rises to the level of an act of obedience and is rewarded likewise.