Collected from Imam al-Tirmidhī, which he has authenticated, upon the authority of Abū Dardaa that the Prophet (sallāllahu ʿalayhi wa-sallam) said, “There is nothing that will weigh heavier on the scales than good character”.
Also showing the importance of having love for one another is that from the seven who will be shaded on the Day of Judgement will be two men who meet upon love for the sake of Allāh and they depart while they still love on another.
From the etiquettes of good companionship is showing gentleness, kindness, and mercy to one another. This applies even more to those who have the same ʿAqīdah as the Salaf, as well as their Methodology.
Allāh says in the Qurʾān,
مُّحَمَّدٌ رَّسُولُ اللَّهِ ۚ وَالَّذِينَ مَعَهُ أَشِدَّاءُ عَلَى الْكُفَّارِ رُحَمَاءُ بَيْنَهُمْ ۖ تَرَاهُمْ رُكَّعًا سُجَّدًا
Muḥammad is the Messenger of Allāh, those those who are with him are severe against disbelievers, and merciful amongst themselves. You see them bowing and falling down prostrate (in prayer)
[Sūrah al-Fath, 48:29]
Shaykh ʿAbdullāh al-Bukhārī mentions that from the etiquettes of good companionship is having a good thought towards one another. This has a strong importance. Many of the people go wrong pertaining to this issue, and go to the extreme in having bad thoughts with one another. This causes a lot of harm and division, which removes justice and fairness between one another. Look at your brother in a good way, and make excuses for them. Allāh says,
ٌيَا أَيُّهَا الَّذِينَ آمَنُوا اجْتَنِبُوا كَثِيرًا مِّنَ الظَّنِّ إِنَّ بَعْضَ الظَّنِّ إِثْم
O you who believe! Avoid much suspicions, indeed some suspicions are sins.
[Sūrah al-Ḥujurāt 49:12]
If someone is looking for companions that have no mistakes or faults, then he will never have friends.
The believer should find excuses for his brother as has been mentioned by Imām Ibn al-Mubārik (raḥimahullāh). The troublemaker finds the faults of the brothers and doesn’t even give them the chance to explain themselves.
This is from the attributes of those who are not upon a clear manhaj, who have gone astray. It is from the Shayṭān to lead astray the believer using suspicion.