The importance of showing kindness and mercy towards each other.

 The importance of showing kindness and mercy towards each other.

Allah says in Quran,

Al-Hujurat 49:10

إِنَّمَا ٱلۡمُؤۡمِنُونَ إِخۡوَةࣱ فَأَصۡلِحُواْ بَيۡنَ أَخَوَيۡكُمۡۚ وَٱتَّقُواْ ٱللَّهَ لَعَلَّكُمۡ تُرۡحَمُونَ 

The believers are but brothers, so make settlement between your brothers. And fear Allāh that you may receive mercy.

Allah says,

Aal-e-Imran 3:159

فَبِمَا رَحۡمَةࣲ مِّنَ ٱللَّهِ لِنتَ لَهُمۡۖ وَلَوۡ كُنتَ فَظًّا غَلِيظَ ٱلۡقَلۡبِ لَٱنفَضُّواْ مِنۡ حَوۡلِكَۖ فَٱعۡفُ عَنۡهُمۡ وَٱسۡتَغۡفِرۡ لَهُمۡ وَشَاوِرۡهُمۡ فِي ٱلۡأَمۡرِۖ فَإِذَا عَزَمۡتَ فَتَوَكَّلۡ عَلَى ٱللَّهِۚ إِنَّ ٱللَّهَ يُحِبُّ ٱلۡمُتَوَكِّلِينَ

So by mercy from Allāh, [O Muḥammad], you were lenient with them. And if you had been rude [in speech] and harsh in heart, they would have disbanded from about you. So pardon them and ask forgiveness for them and consult them in the matter. And when you have decided, then rely upon Allāh. Indeed, Allāh loves those who rely [upon Him].

Allah S.W.T call the believers as brothers in faith.

Allah says in Quran,

Al-Ahzab 33:5

ٱدۡعُوهُمۡ لِأٓبَآئِهِمۡ هُوَ أَقۡسَطُ عِندَ ٱللَّهِۚ فَإِن لَّمۡ تَعۡلَمُوٓاْ ءَابَآءَهُمۡ فَإِخۡوَٰنُكُمۡ فِي ٱلدِّينِ وَمَوَٰلِيكُمۡۚ وَلَيۡسَ عَلَيۡكُمۡ جُنَاحࣱ فِيمَآ أَخۡطَأۡتُم بِهِۦ وَلَٰكِن مَّا تَعَمَّدَتۡ قُلُوبُكُمۡۚ وَكَانَ ٱللَّهُ غَفُورࣰا رَّحِيمًا

Call them[1] by [the names of] their fathers; it is more just in the sight of Allāh. But if you do not know their fathers - then they are [still] your brothers in religion and those entrusted to you. And there is no blame upon you for that in which you have erred but [only for] what your hearts intended. And ever is Allāh Forgiving and Merciful.

This Ayah was talking about the adopted son when Allah s.w.t forbade adoption and said there is nothing like adoption and rather the prophet PBUH should call Zayd ibn Haritha by his father's name and if he does not know his father's name to call him his brother in faith.

As we know, a Muslim must be kind and mercy to his fellow Muslim

As reported in Hadith,

Narrated Abu Musa:

The Prophet (ﷺ) said, "A faithful believer to a faithful believer is like the bricks of a wall, enforcing eachother." While (saying that) the Prophet (ﷺ) clasped his hands, by interlacing his fingers.

Sahih al-Bukhari 481.