Musnad Ahmad 937:193

Wahb ibn Jarir narrated to us, Mahdi ibn Maymun narrated to us, from Wasil, from Yahya ibn Aqil, from Yahya ibn Ya'mar, from Abu al-Aswad al-Dili, from Abu Dharr, who said: It was said: "O Messenger of Allah, the wealthy have taken away the rewards. They pray as we pray, and they fast as we fast, and they give charity from their surplus wealth." He said: "Has Allah not made for you that which you may give as charity? Indeed, in every *tasbihah* (saying SubhanAllah) is a charity, and in every *takbirah* (saying Allahu Akbar) is a charity, and in every *tahlilah* (saying La ilaha illa Allah) is a charity, and in every *tahmidah* (saying Alhamdulillah) is a charity, and enjoining good is a charity, and forbidding evil is a charity, and in the sexual intercourse of one of you is a charity." They said: "O Messenger of Allah, one of us fulfills his desire and has a reward in it?" He said: "Do you see, if he were to place it in the forbidden, would he not have a sin upon him?" They said: "Yes." He said: "Likewise, if he places it in the lawful, he has a reward."