Hadith: Has Allah not provided for you that which you can give as charity? Every Tasbīh (saying: Glory be to Allah) is charity; every Takbīr (saying: Allah is the Greatest) is charity; every Tahmīd (saying: Praise be to Allah) is charity; and every Tahlīl (saying: There is no God but Allah) is charity. Enjoining good is charity, forbidding evil is charity, and even in fulfilling the sexual desire of one of you there is charity

عَنْ أَبِي ذَرٍّ رضي الله عنه:
أَنَّ نَاسًا مِنْ أَصْحَابِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالُوا لِلنَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: يَا رَسُولَ اللهِ، ذَهَبَ أَهْلُ الدُّثُورِ بِالْأُجُورِ، يُصَلُّونَ كَمَا نُصَلِّي، وَيَصُومُونَ كَمَا نَصُومُ، وَيَتَصَدَّقُونَ بِفُضُولِ أَمْوَالِهِمْ، قَالَ: «أَوَلَيْسَ قَدْ جَعَلَ اللهُ لَكُمْ مَا تَصَّدَّقُونَ؟ إِنَّ بِكُلِّ تَسْبِيحَةٍ صَدَقَةً، وَكُلِّ تَكْبِيرَةٍ صَدَقَةً، وَكُلِّ تَحْمِيدَةٍ صَدَقَةً، وَكُلِّ تَهْلِيلَةٍ صَدَقَةً، وَأَمْرٌ بِالْمَعْرُوفِ صَدَقَةٌ، وَنَهْيٌ عَنْ مُنْكَرٍ صَدَقَةٌ، وَفِي بُضْعِ أَحَدِكُمْ صَدَقَةٌ»، قَالُوا: يَا رَسُولَ اللهِ، أَيَأتِي أَحَدُنَا شَهْوَتَهُ وَيَكُونُ لَهُ فِيهَا أَجْرٌ؟ قَالَ: «أَرَأَيْتُمْ لَوْ وَضَعَهَا فِي حَرَامٍ أَكَانَ عَلَيْهِ فِيهَا وِزْرٌ؟ فَكَذَلِكَ إِذَا وَضَعَهَا فِي الْحَلَالِ كَانَ لَهُ أَجْرٌ».
[صحيح] - [رواه مسلم] - [صحيح مسلم: 1006]

Abu Dharr (may Allah be pleased with him) reported:
Some of the Companions of the Prophet (may Allah's peace and blessings be upon him) said to the Prophet (may Allah's peace and blessings be upon him): O Messenger of Allah, the wealthy have taken all the rewards. They pray as we pray, fast as we fast, and give charity from their surplus wealth. He said: "Has Allah not provided for you that which you can give as charity? Every Tasbīh (saying: Glory be to Allah) is charity; every Takbīr (saying: Allah is the Greatest) is charity; every Tahmīd (saying: Praise be to Allah) is charity; and every Tahlīl (saying: There is no God but Allah) is charity. Enjoining good is charity, forbidding evil is charity, and even in fulfilling the sexual desire of one of you there is charity." They said: O Messenger of Allah, does one of us fulfill his desire and get rewarded for it? He said: "Do you not see that if he were to fulfill it in a forbidden way, would he incur a sin? Similarly, if he fulfills it lawfully, he will have a reward."
[Authentic hadith] - [Narrated by Muslim] - [Sahih Muslim - 1006]

Explanation

Some of the Prophet's poor Companions complained to the Prophet (may Allah's peace and blessings be upon him) about their poverty and inability to give money in charity to attain abundant rewards, as those attained by their wealthy brothers, and to perform good deeds like them, for they pray as we pray, fast as we fast, and give charity from their surplus wealth, but we do not! The Prophet (may Allah's peace and blessings be upon him) guided them to charities they could afford, as he (may Allah's peace and blessings be upon him) said: Has Allah not provided for you that which you can give as charity for yourselves?! Saying (Subhānallāh) (Glory be to Allah) is counted as charity for you; also saying (Allāhu Akbar) (Allah is the Greatest) is charity; saying (Alhamdulillāh) (praise be to Allah) is charity; and saying (La ilāha illallāh) (There is no god but Allah) is charity. (Enjoining good) is charity, and (forbidding evil) is charity, and even if one of you has sexual intercourse with his wife, there is charity. They were amazed and said: O Messenger of Allah, does one of us fulfill his desire and receive a reward for it?! He said: Do you not see that if he were to fulfill it in a forbidden way, like adultery or otherwise, would he incur a sin? Similarly, if he fulfills it lawfully, he will have a reward.