Hadith: The polytheists said to us: I see that your companion teaches you everything, even how to relieve yourselves. He said: Yes, indeed. He forbade us from using our right hand for cleaning ourselves, or facing the Qiblah (direction of prayer), and he prohibited us from using dung and bones, and said: @"None of you should clean himself with less than three stones."

عَنْ سَلْمَانَ رَضيَ اللهُ عنه قَالَ:
قَالَ لَنَا الْمُشْرِكُونَ: إِنِّي أَرَى صَاحِبَكُمْ يُعَلِّمُكُمْ حَتَّى يُعَلِّمَكُمُ الْخِرَاءَةَ، فَقَالَ: أَجَلْ، إِنَّهُ نَهَانَا أَنْ يَسْتَنْجِيَ أَحَدُنَا بِيَمِينِهِ، أَوْ يَسْتَقْبِلَ الْقِبْلَةَ، وَنَهَى عَنِ الرَّوْثِ وَالْعِظَامِ وَقَالَ: «لَا يَسْتَنْجِي أَحَدُكُمْ بِدُونِ ثَلَاثَةِ أَحْجَارٍ».
[صحيح] - [رواه مسلم] - [صحيح مسلم: 262]

Salmān (may Allah be pleased with him) reported:
The polytheists said to us: I see that your companion teaches you everything, even how to relieve yourselves. He said: Yes, indeed. He forbade us from using our right hand for cleaning ourselves, or facing the Qiblah (direction of prayer), and he prohibited us from using dung and bones, and said: "None of you should clean himself with less than three stones."
[Authentic hadith] - [Narrated by Muslim] - [Sahih Muslim - 262]

Explanation

Salmān al-Fārisi (may Allah be pleased with him) reported: The polytheists mockingly said to us: Your Prophet teaches you everything; he even teaches you how to relieve yourselves, whether in urinating or defecating! Salmān said: Yes, he taught us the etiquette of relieving oneself. Among what he taught us is that he (may Allah's peace and blessings be upon him) forbade us from cleaning ourselves with the right hand after relieving ourselves, out of respect and to keep it clean from impurity. He also forbade us from facing the Ka‘bah while urinating or defecating. And he forbade us from using animal dung or bones for Istijmār (dry cleansing). Furthermore, he instructed that one in a state of Hadath (ritual impurity) should not suffice with fewer than three stones when performing Istijmār.

Benefits from the Hadith

1. Highlighting the comprehensiveness and perfection of the Islamic Shariah in addressing everything that people need.
2. Clarification of some of the etiquettes of using the restroom and performing Istinjā’ (cleansing after relieving oneself).
3. The prohibition of facing the Qiblah while urinating or defecating because of his statement: "He forbade us," and the basic ruling is that prohibition indicates unlawfulness.
4. The prohibition of making Istinjā’ or Istijmār with the right hand out of respect for it.
5. The superiority of the right hand over the left, because the left hand is used for removing impurities and filth, while the right hand is used for everything else.
6. It is obligatory to remove impurity using water or stones, whether the impurity is small or large in amount.
7. The prohibition of using fewer than three stones for Istijmār, because fewer than three stones usually do not achieve proper cleansing.
8. Everything that achieves the intended purpose of purification and cleansing is sufficient. The Prophet (may Allah's peace and blessings be upon him) specifically mentioned stones because they were the most commonly used; thus, the ruling is not restricted to them alone.
9. It is recommended to end Istijmār with an odd number. So, if cleanliness is achieved with four, it is recommended to add a fifth, and so on, based on the statement of the Prophet (may Allah's peace and blessings be upon him): (Whoever performs Istijmār, let him do so with an odd number).
10. The prohibition of using animal dung for Istijmār is because it is either impure or because it serves as fodder for the animals of the jinn.
11. The prohibition of using bones for Istijmār is because it is either impure or serves as food for the jinn themselves.