Riyad as-Salihin 120

Abu Dharr (May Allah be pleased with him) reported: Some people said to Messenger of Allah (ﷺ): "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 (ﷺ)) 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". [Muslim].