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

الترغيب في الإصلاح بين الناس

Encouragement to reconcile between people.

Source: al-Targhīb wal-Tarhīb 3/487

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

تَعْدِلُ بَيْنَ الِاثْنَيْنِ صَدَقَةٌ

Being just between two people is charity.

Source: Ṣaḥīḥ al-Bukhārī 2827, Grade: Muttafaqun Alayhi

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

أَلَا أُخْبِرُكُمْ بِأَفْضَلَ مِنْ دَرَجَةِ الصِّيَامِ وَالصَّلَاةِ وَالصَّدَقَةِ

Shall I not tell you of what is better in degree than extra fasting, prayer, and charity?

They said, “Of course!” The Prophet said:

صَلَاحُ ذَاتِ الْبَيْنِ فَإِنَّ فَسَادَ ذَاتِ الْبَيْنِ هِيَ الْحَالِقَةُ

Reconciliation between people. Verily, corrupted relations between people is the razor.

Source: Sunan al-Tirmidhī 2509, Grade: Sahih

In another narration, the Prophet said:

الحَسَدُ وَالبَغْضَاءُ هِيَ الحَالِقَةُ لاَ أَقُولُ تَحْلِقُ الشَّعَرَ وَلَكِنْ تَحْلِقُ الدِّينَ

Envy and hatred are the razor. I do not say they shave hair. Rather, they shave away the religion.

Source: Sunan al-Tirmidhī 2510, Grade: Sahih

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

لَيْسَ الْكَذَّابُ الَّذِي يُصْلِحُ بَيْنَ النَّاسِ فَيَنْمِي خَيْرًا أَوْ يَقُولُ خَيْرًا

He is not a liar who reconciles people by spreading good, or saying something good.

Source: Ṣaḥīḥ al-Bukhārī 2546, Grade: Muttafaqun Alayhi

Ibn Hajar commented on this tradition, writing:

الْعُلَمَاءُ الْمُرَادُ هُنَا أَنَّهُ يُخْبِرُ بِمَا عَلِمَهُ مِنَ الْخَيْرِ وَيَسْكُتُ عَمَّا عَلِمَهُ مِنَ الشَّرِّ وَلَا يَكُونُ ذَلِكَ كَذِبًا لِأَنَّ الْكَذِبَ الْإِخْبَارُ بِالشَّيْءِ عَلَى خِلَافِ مَا هُـوَ بِهِ

The scholars said the meaning here is that he reports good things he knows and is silent about bad things. He would not be a liar, since a liar claims something different than it actually is.

Source: Fatḥ al-Bārī 2546

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

مَا عَمِلَ ابْنُ آدَمَ شَيْئًا أَفْضَلَ مِنَ الصَّلاةِ وَصَلاحِ ذَاتِ الْبَيْنِ وَخُلُقٍ حَسَنٍ

The son of Adam does not act with anything better than prayer, reconciliation between people, and good character.

Source: Shu’ab al-Imān 10333, Grade: Sahih

Abdullah ibn Amr reported: The Messenger of Allah, peace and blessings be upon him, said:

أَفْضَلُ الصَّدَقَةِ إِصْلَاحُ ذَاتِ الْبَيِّنِ

The best act of charity is to reconcile people.

Source: al-Mu’jam al-Kabīr 31, Grade: Sahih li ghayri

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

أَلا أَدُلُّكَ عَلَى صَدَقَةٍ يُحِبُّهَا اللَّهُ وَرَسُولُهُ تُصْلِحُ بَيْنَ النَّاسِ إِذَا تَبَاغَضُوا وَتَفَاسَدُوا

Shall I not tell you of a charity beloved to Allah and his messenger? Reconcile people when there is hatred and corruption between them.

Source: al-Mu’jam al-Kabīr 3824, Grade: Hasan li ghayri

In another narration, the Prophet said:

تُصْلِحُ بَيْنَ النَّاسِ إِذَا تَفَاسَدُوا وَتُقَرِّبُ بَيْنَهُمْ إِذَا تَبَاعَدُو

That you reconcile between people if their relations are corrupted, and you bring them together when they are far apart.

Source: Shu’ab al-Imān 10336, Grade: Hasan li ghayri