[Machine] The Prophet ﷺ said, "When one of you enters the restroom, do not use his right hand for istinja and do not touch his private parts with his right hand." This hadith is narrated by Hisham al-Dastuwa'i in the two authentic narrations and is also reported by Salman and Abu Hurairah.  

أَنَّ النَّبِيَّ ﷺ قَالَ إِذَا أَتَى أَحَدُكُمُ الْخَلَاءَ فَلَا يَسْتَنْجِيَنَّ بِيَمِينِهِ وَلَا يَمَسَّ ذَكَرَهُ بِيَمِينِهِ مُخَرَّجٌ فِي الصَّحِيحَيْنِ مِنْ حَدِيثِ هِشَامٍ الدَّسْتُوَائِيِّ وَرُوِّينَاهُ مِنْ حَدِيثِ سَلْمَانَ وَأَبِي هُرَيْرَةَ  

I see that your friend even teaches you about the excrement. He replied; Yes, he has in fact forbidden us that anyone amongst us should cleanse himself with his right hand, or face the Qibla. He has forbidden the use of dung or bone for it, and he has also instructed us not to use less than three pebbles (for this purpose). (Using translation from Muslim 262b)   

قَالَ لَهُ الْمُشْرِكُونَ إِنَّا نَرَى صَاحِبَكُمْ يُعَلِّمُكُمْ حَتَّى يُعَلِّمَكُمُ الْخِرَاءَةَ؟ قَالَ أَجَلْ إِنَّهُ نَهَانَا أَنْ يَسْتَنْجِيَ أَحَدُنَا بِيَمِينِهِ وَأَنْ يَسْتَقْبِلَ الْقِبْلَةَ وَنَهَانَا عَنِ الرَّوْثِ وَالْعِظَامِ وَقَالَ لَا يَسْتَنْجِ أَحَدُكُمْ بِدُونِ ثَلَاثَةِ أَحْجَارٍ  

The Apostle of Allaah ( sal Allaahu alayhi wa sallam ) as saying: I am like father to you. When any of you goes to privy, he should not face or turn his back towards the qiblah. He should not cleanse with his right hand. He (the Prophet, sal Allaahu alayhi wa sallam) also commanded the Muslims to use three stones and forbade them to use dung or decayed bone. (Using translation from Abū Dāʾūd 8)   

عَنِ النَّبِيِّ ﷺ قَالَ إِنَّمَا أَنَا لَكُمْ مِثْلُ الْوَالِدِ أُعَلِّمُكُمْ فَإِذَا ذَهَبَ أَحَدُكُمُ الْخَلَاءَ فَلَا يَسْتَقْبِلِ الْقِبْلَةَ وَلَا يَسْتَدْبِرْهَا وَلَا يَسْتَنْجِ بِيَمِينِهِ وَكَانَ يَأْمُرُ بِثَلَاثَةِ أَحْجَارٍ وَيَنْهَى عَنِ الرَّوْثِ وَالرِّمَّةِ  

The Prophet ﷺ used his right hand for taking his food and drink and used his left hand for other purposes. (Using translation from Abū Dāʾūd 32)   

حَدَّثَتْنِي حَفْصَةُ زَوْجُ النَّبِيِّ ﷺ أَنَّ رَسُولَ اللهِ ﷺ كَانَ يَجْعَلُ يَمِينَهُ لِطَعَامِهِ وَشَرَابِهِ وَثِيَابِهِ وَيَجْعَلُ يَسَارَهُ لِمَا سِوَى ذَلِكَ  

[Machine] The right hand of the messenger of Allah ﷺ was used for purification, food, and drink, while the left hand was used for other needs and avoiding harm.  

يَدُ رَسُولِ اللهِ ﷺ الْيُمْنَى لِطُهُورِهِ وَطَعَامِهِ وَشَرَابِهِ وَكَانَتِ الْيُسْرَى لِخَلَائِهِ وَمَا كَانَ مِنْ أَذًى هَكَذَا