In every moral code, there is special emphasis on kindness as it’s a powerful instrument that makes interaction among humans gainful, and imparts richness and ethical beauty to social dealings.

Kindness facilitates human understanding and reduces the chances of friction and conflict, which abound in practically every walk of life.

To answer the question, “Who should we be kind to?” The answer is that Islam enjoins kindness towards all individuals, but more so towards certain categories, such as parents and orphans. This quality is particularly stressed in the Quran. This was the advice given to the Children of Israel as evident from the following verse.

وَإِذْ أَخَذْنَا مِيثَـٰقَ بَنِىٓ إِسْرَٰٓءِيلَ لَا تَعْبُدُونَ إِلَّا ٱللَّهَ وَبِٱلْوَٰلِدَيْنِ إِحْسَانًا وَذِى ٱلْقُرْبَىٰ وَٱلْيَتَـٰمَىٰ وَٱلْمَسَـٰكِينِ وَقُولُوا۟ لِلنَّاسِ حُسْنًا وَأَقِيمُوا۟ ٱلصَّلَوٰةَ وَءَاتُوا۟ ٱلزَّكَوٰةَ ثُمَّ تَوَلَّيْتُمْ إِلَّا قَلِيلًا مِّنكُمْ وَأَنتُم مُّعْرِضُونَ
“And (remember) when We made a covenant with the Children of Israel, (saying) Worship none save Allah, and be good to parents and to kindred and to orphans and the needy, and speak kindly to mankind; and establish worship and pay the poor their due. Then, after that, you slid back save a few of you, being averse.” (Al Baqarah 2: 83)

Kindness must always be shown when dealing with parents and the near kindred.
كُتِبَ عَلَيْكُمْ إِذَا حَضَرَ أَحَدَكُمُ ٱلْمَوْتُ إِن تَرَكَ خَيْرًا ٱلْوَصِيَّةُ لِلْوَٰلِدَيْنِ وَٱلْأَقْرَبِينَ بِٱلْمَعْرُوفِ ۖ حَقًّا عَلَى ٱلْمُتَّقِينَ
“It is prescribed for you, when one of you approaches death, if he leaves wealth that he bequeath unto parents and near relatives in kindness. (This is) a duty for all those who ward off (evil).” (Al Baqarah 2: 180)

Kindness must never be forgotten towards parents even when they attain old age.
وَقَضَىٰ رَبُّكَ أَلَّا تَعْبُدُوٓا۟ إِلَّآ إِيَّاهُ وَبِٱلْوَٰلِدَيْنِ إِحْسَـٰنًا ۚ إِمَّا يَبْلُغَنَّ عِندَكَ ٱلْكِبَرَ أَحَدُهُمَآ أَوْ كِلَاهُمَا فَلَا تَقُل لَّهُمَآ أُفٍّ وَلَا تَنْهَرْهُمَا وَقُل لَّهُمَا قَوْلًا كَرِيمًا
“Your Lord has decreed, that you worship none save Him, and (that you show) kindness to parents. If one of them or both attain old age … speak unto them with a gracious word.” (Al Israa 17: 23)

Acts of charity must also be accompanied by words of kindness.
ٱلَّذِينَ يُنفِقُونَ أَمْوَٰلَهُمْ فِى سَبِيلِ ٱللَّهِ ثُمَّ لَا يُتْبِعُونَ مَآ أَنفَقُوا۟ مَنًّا وَلَآ أَذًى ۙ لَّهُمْ أَجْرُهُمْ عِندَ رَبِّهِمْ وَلَا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ
“Those who spend their wealth for the cause of Allah and afterward make not reproach and injury to follow that which they have spent, their reward is with their Lord, and there shall be no fear to come upon them, neither shall they grieve.”(Al Baqarah 2: 262)

The Quran even enjoins Muslims to speak kindly to the downtrodden or the intellectually challenged.

وَلَا تُؤْتُوا۟ ٱلسُّفَهَآءَ أَمْوَٰلَكُمُ ٱلَّتِى جَعَلَ ٱللَّهُ لَكُمْ قِيَـٰمًا وَٱرْزُقُوهُمْ فِيهَا وَٱكْسُوهُمْ وَقُولُوا۟ لَهُمْ قَوْلًا مَّعْرُوفًا
And do not entrust to those who are weak of judgment the possessions which Allah has placed in your charge for [their] support; but let them have their sustenance therefrom, and clothe them, and speak unto them in a kindly way. (An Nisaa 4: 5)
In a marital relationship, man has been given the responsibility to protect and to provide for his wife, and to some degree, be responsible for her actions. He is to discharge his duties towards the woman with kindness, taking care never to abuse his role. The following injunctions explain this point.

وَإِنِ ٱمْرَأَةٌ خَافَتْ مِنۢ بَعْلِهَا نُشُوزًا أَوْ إِعْرَاضًا فَلَا جُنَاحَ عَلَيْهِمَآ أَن يُصْلِحَا بَيْنَهُمَا صُلْحًا ۚ وَٱلصُّلْحُ خَيْرٌ ۗ وَأُحْضِرَتِ ٱلْأَنفُسُ ٱلشُّحَّ ۚ وَإِن تُحْسِنُوا۟ وَتَتَّقُوا۟ فَإِنَّ ٱللَّهَ كَانَ بِمَا تَعْمَلُونَ خَبِيرًا
“If a woman fears ill treatment from her husband, or desertion, it is no sin for them if they make terms of peace between themselves. Peace is better. But greed has been made present in the minds (of men). If you do good and keep from evil, lo! Allah is ever informed of what you do.”(An Nisaa 4: 128)

Allah also urges the Prophet ﷺ to stress kindness among believers in their daily actions.
خُذِ ٱلْعَفْوَ وَأْمُرْ بِٱلْعُرْفِ وَأَعْرِضْ عَنِ ٱلْجَـٰهِلِينَ
“Keep to forgiveness (O Mohammad), and enjoin kindness, and turn away from the ignorant.”(Al A`raf 7: 199)

All those in a position of authority are not only to embody kindness in their own conduct, but they must also enjoin it to others. Authority must never be abused in positions of government and administration. If government officials are not sympathetic to the needs of the people, politics remains unstable, giving rise to despotism or anarchy

ٱلَّذِينَ إِن مَّكَّنَّـٰهُمْ فِى ٱلْأَرْضِ أَقَامُوا۟ ٱلصَّلَوٰةَ وَءَاتَوُا۟ ٱلزَّكَوٰةَ وَأَمَرُوا۟ بِٱلْمَعْرُوفِ وَنَهَوْا۟ عَنِ ٱلْمُنكَرِ ۗ وَلِلَّهِ عَـٰقِبَةُ ٱلْأُمُورِ
“Those who, if We give them power in the land, establish worship and pay the poor-due and enjoin kindness and forbid inequity. And with Allah rests the outcome of all affairs.”(Al Hajj 22: 41).

Towards people of other faiths, the Quran suggests tolerance and kindness as the preferred line of action to be adopted by Muslims. Islam strives to maintain a healthy balance in society in each and every facet of human dealing. Its injunctions are aimed at creating healthy relationships and close ties of kinship among people. Islam teaches that our relationships must be built on a foundation of kindness and compassion.