It is collected by Muslim in his ‘Saheeh’ from Abu Dharr (radi Allāhu anhu): Some of the companions of the Messenger of Allāh (صلى الله عليه وسلم) said:
‘O Messenger of Allāh, the affluent have made off with the rewards, they pray as we pray they fast as we fast, and they give away in charity the extra of their wealth.’
He (صلى الله عليه وسلم) said:
‘Has not Allāh made things for you to give away in charity?
Every Tasbihah (saying: Subhāna Allāh) is a charity, every Takbirah (saying: Allāhu Akbar) is a charity, every Tahmidah (saying: al-Hamdu lillāh) is a charity, and every Tahlilah (saying: Lā ilāh illa Allāh) is a charity, to enjoin a good action is a charity, to forbid an evil action is a charity, and in having relations with your wife is a charity.’