Al-Mundhiri recorded the following chapter in his book Al-Targhib wal-Tarhib:

الترغيب في الجليس الصالح والترهيب من الجليس السيّئ

Encouragement to keep righteous company and discouragement of bad company.

Source: al-Targhīb wal-Tarhīb 4/49

Abu Musa reported: The Prophet, peace and blessings be upon him, said:

إِنَّمَا مَثَلُ الْجَلِيسِ الصَّالِحِ وَالْجَلِيسِ السَّوْءِ كَحَامِلِ الْمِسْكِ وَنَافِخِ الْكِيرِ فَحَامِلُ الْمِسْكِ إِمَّا أَنْ يُحْذِيَكَ وَإِمَّا أَنْ تَبْتَاعَ مِنْهُ وَإِمَّا أَنْ تَجِدَ مِنْهُ رِيحًا طَيِّبَةً وَنَافِخُ الْكِيرِ إِمَّا أَنْ يُحْرِقَ ثِيَابَكَ وَإِمَّا أَنْ تَجِدَ رِيحًا خَبِيثَةً

Verily, the parable of good company and a bad company is only that of a seller of musk and a blacksmith. The seller of musk will give you some perfume, you will buy some, or you will notice a good smell. As for the blacksmith, he will burn your clothes or you will notice a bad smell.

Source: Ṣaḥīḥ al-Bukhārī 1995, Grade: Muttafaqun Alayhi

Abu Musa reported: The Prophet, peace and blessings be upon him, said:

مَثَلُ الْمُؤْمِنِ الَّذِي يَقْرَأُ الْقُرْآنَ مَثَلُ الأُتْرُجَّةِ رِيحُهَا طَيِّبٌ وَطَعْمُهَا طَيِّبٌ وَمَثَلُ الْمُؤْمِنِ الَّذِي لاَ يَقْرَأُ الْقُرْآنَ مَثَلُ التَّمْرَةِ لاَ رِيحَ لَهَا وَطَعْمُهَا حُلْوٌ وَمَثَلُ الْمُنَافِقِ الَّذِي يَقْرَأُ الْقُرْآنَ مَثَلُ الرَّيْحَانَةِ رِيحُهَا طَيِّبٌ وَطَعْمُهَا مُرٌّ وَمَثَلُ الْمُنَافِقِ الَّذِي لاَ يَقْرَأُ الْقُرْآنَ كَمَثَلِ الْحَنْظَلَةِ لَيْسَ لَهَا رِيحٌ وَطَعْمُهَا مُرٌّ

The parable of the believer who recites the Quran is that of a citrus fruit, which tastes good and has a pleasant scent. The parable of the believer who does not recite the Quran is that of a date, which has no scent but tastes good. The parable of a hypocrite who recites the Quran is that of basil, which has a pleasant scent but tastes bitter. The parable of the hypocrite who does not recite the Quran is that of a vine, which has no scent and tastes bitter.

Source: Ṣaḥīḥ al-Bukhārī 4732, Grade: Muttafaqun Alayhi

Anas reported: The Messenger of Allah, peace and blessings be upon him, said:

مَثَلُ الْمُؤْمِنِ الَّذِي يَقْرَأُ الْقُرْآنَ مَثَلُ الْأُتْرُجَّةِ رِيحُهَا طَيِّبٌ وَطَعْمُهَا طَيِّبٌ وَمَثَلُ الْمُؤْمِنِ الَّذِي لَا يَقْرَأُ الْقُرْآنَ كَمَثَلِ التَّمْرَةِ طَعْمُهَا طَيِّبٌ وَلَا رِيحَ لَهَا وَمَثَلُ الْفَاجِرِ الَّذِي يَقْرَأُ الْقُرْآنَ كَمَثَلِ الرَّيْحَانَةِ رِيحُهَا طَيِّبٌ وَطَعْمُهَا مُرٌّ وَمَثَلُ الْفَاجِرِ الَّذِي لَا يَقْرَأُ الْقُرْآنَ كَمَثَلِ الْحَنْظَلَةِ طَعْمُهَا مَرٌّ وَلَا رِيحَ لَهَا وَمَثَلُ الْجَلِيسِ الصَّالِحِ كَمَثَلِ صَاحِبِ الْمِسْكِ إِنْ لَمْ يُصِبْكَ مِنْهُ شَيْءٌ أَصَابَكَ مِنْ رِيحِهِ وَمَثَلُ جَلِيسِ السُّوءِ كَمَثَلِ صَاحِبِ الْكِيرِ إِنْ لَمْ يُصِبْكَ مِنْ سَوَادِهِ أَصَابَكَ مِنْ دُخَانِهِ

The parable of the believer who recites the Quran is that of citron, who fragrance and taste are pleasant. The parable of the believer who does not recite the Quran is that of a date-fruit, whose taste is sweet and has no fragrance. The parable of the wicked who recites the Quran is that of basil, whose fragrance is pleasant and taste is bitter. The parable of the wicked who does not recite the Quran is that of a vine, whose taste is bitter and has no fragrance. The parable of good company is that of a seller of musk; he will smell its fragrance even if he does not buy anything. The parable of bad company is that of a blacksmith; he will smell its smoke even if he is not touched by its ashes.

Source: Sunan Abī Dāwūd 4829, Grade: Sahih

Abu Sa’id al-Khudri reported: The Messenger of Allah, peace and blessings be upon him, said:

إِيَّاكُمْ وَالْجُلُوسَ عَلَى الطُّرُقَاتِ

Beware of loitering in the roads.

They said, “O Messenger of Allah, we have nowhere else to sit and talk.” The Prophet said:

أَبَيْتُمْ إِلَّا الْمَجَالِسَ فَأَعْطُوا الطَّرِيقَ حَقَّهَا

If you insist, then give the road its rights.

They said, “What are its rights, O Messenger of Allah?” The Prophet said:

غَضُّ الْبَصَرِ وَكَفُّ الْأَذَى وَرَدُّ السَّلَامِ وَأَمْرٌ بِالْمَعْرُوفِ وَنَهْيٌ عَنْ الْمُنْكَرِ

Lower the gaze, refrain from harm, return greetings of peace, enjoin good and forbid evil.

Source: Ṣaḥīḥ al-Bukhārī 2333, Grade:Muttafaqun Alayhi

Abu Sa’id al-Khudri reported: The Prophet, peace and blessings be upon him, said:

خَيْرُ الْمَجَالِسِ أَوْسَعُهَا

The best gatherings make room for the most people.

Source: Sunan Abī Dāwūd 4820, Grade: Sahih

Al-Sharid ibn Suwayd reported: The Messenger of Allah, peace and blessings be upon him, passed by me while I was sitting with my left hand behind my back and leaning upon it. The Prophet said:

أَتَقْعُدُ قِعْدَةَ الْمَغْضُوبِ عَلَيْهِمْ

Do you sit like one with whom Allah is angry?

Source: Sunan Abī Dāwūd 4848, Grade: Sahih

Abu Huraira reported: The Prophet, peace and blessings be upon him, said:

إِذَا قَامَ الرَّجُلُ مِنْ مَجْلِسٍ ثُمَّ رَجَعَ إِلَيْهِ فَهُوَ أَحَقُّ بِهِ

If a man stands from his seat and later returns to it, he is more entitled to it.

Source: Ṣaḥīḥ Muslim 2179, Grade: Sahih