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

الترغيب في طلاقة الوجه وطيب الكلام

Encouragement to show a cheerful face and speak kind words.

Source: al-Targhīb wal-Tarhīb 3/421

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

لاَ تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا وَلَوْ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ

Do not belittle any good deed, even meeting your brother with a cheerful face.

Source: Ṣaḥīḥ Muslim 2626, Grade: Sahih

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

كُلُّ مَعْرُوفٍ صَدَقَةٌ وَإِنَّ مِنْ الْمَعْرُوفِ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ وَأَنْ تُفْرِغَ مِنْ دَلْوِكَ فِي إِنَاءِ أَخِيكَ

Every good deed is charity. Verily, it is a good deed to meet your brother with a cheerful face, and to pour what is left from your bucket into the vessel of your brother.

Source: Sunan al-Tirmidhī 1970, Grade: Sahih

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

تَبَسُّمُكَ فِي وَجْهِ أَخِيكَ لَكَ صَدَقَةٌ وَأَمْرُكَ بِالْمَعْرُوفِ وَنَهْيُكَ عَنْ الْمُنْكَرِ صَدَقَةٌ وَإِرْشَادُكَ الرَّجُلَ فِي أَرْضِ الضَّلَالِ لَكَ صَدَقَةٌ وَبَصَرُكَ لِلرَّجُلِ الرَّدِيءِ الْبَصَرِ لَكَ صَدَقَةٌ وَإِمَاطَتُكَ الْحَجَرَ وَالشَّوْكَةَ وَالْعَظْمَ عَنْ الطَّرِيقِ لَكَ صَدَقَةٌ وَإِفْرَاغُكَ مِنْ دَلْوِكَ فِي دَلْوِ أَخِيكَ لَكَ صَدَقَةٌ

Smiling in the face of your brother is your charity. Enjoining good and forbidding evil is charity. Guiding a lost man through the land is your charity. Lending your eyesight to a man who cannot see well is your charity. Removing rocks, thorns, and bones from the road is your charity. Pouring your leftovers into the vessel of your brother is your charity.

Source: Sunan al-Tirmidhī 1956, Grade: Sahih

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

إِنَّ تَبَسُّمَكَ فِي وَجْهِ أَخِيكَ صَدَقَةٌ وَإِمَاطَتَكَ الْأَذَى عَنِ الطَّرِيقِ يُكْتَبُ لَكَ صَدَقَةٌ وَإِنَّ إِفْرَاغَكَ فِي دَلْوِ أَخِيكَ صَدَقَةٌ وَأَمْرَكَ بِالْمَعْرُوفِ وَنَهْيَكَ عَنِ الْمُنْكَرِ لَكَ صَدَقَةٌ وَإِرْشَادَكَ الضَّالَّةَ صَدَقَةٌ

Verily, your smile in the face of your brother is charity. Lifting harming things from the road is recorded for you as charity. Pouring your leftovers in the vessel of your brother is charity. Enjoining good and forbidding evil is your charity. Guiding a lost person is charity.

Source: al-Mu’jam al-Awsaṭ 8342, Grade: Sahih li ghayrihi

Jabir ibn Salim reported: I came to the Messenger of Allah, peace and blessings be upon him, and I said, “O Messenger of Allah, we are people of the desert. Teach us something with which Allah will benefit us.” The Prophet said:

لا تَحْقِرَنَّ مِنَ الْمَعْرُوفِ شَيْئًا وَلَوْ أَنْ تُفْرِغَ مِنْ دَلْوِكَ فِي إِنَاءِ الْمُسْتَسْقِي وَلَوْ أَنْ تُكَلِّمَ أَخَاكَ وَوَجْهُكَ إِلَيْهِ مُنْبَسِطٌ وَإِيَّاكَ وَإِسْبَالَ الإِزَارِ فَإِنَّهُ مِنَ الْمَخِيلَةِ وَلا يُحِبُّهَا اللَّهُ وَإِنِ امْرُؤٌ شَتَمَكَ بِمَا يَعْلَمُ فِيكَ فَلا تَشْتُمْهُ بِمَا تَعْلَمُ فِيهِ فَإِنَّ أَجْرَهُ لَكَ وَوَبَالَهُ عَلَى مَنْ قَالَهُ

Do not belittle any good deed, even pouring your leftovers into another’s cistern, even speaking to your brother while smiling at him. Beware of trailing your garment; it is a form of vanity that Allah does not like. If a man insults you with what he knows about you, do not insult him by what you know about him. Verily, you will have a reward and the penalty is upon the one who said it.

Source: Ṣaḥīḥ Ibn Ḥibbān 527, Grade: Sahih

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

وَالْكَلِمَةُ الطَّيِّبَةُ صَدَقَةٌ

A kind word is charity.

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

‘Adi ibn Hatim reported: The Prophet, peace and blessings be upon him, said:

اتَّقُوا النَّارَ وَلَوْ بِشِقِّ تَمْرَةٍ فَمَنْ لَمْ يَجِدْ فَبِكَلِمَةٍ طَيِّبَةٍ

Guard yourself from the Hellfire, even with half of a date in charity. If he cannot find it, then with a kind word.

Source: Ṣaḥīḥ al-Bukhārī 6195, Grade: Muttafaqun Alayhi

Abu Shurayh reported: He said, “O Messenger of Allah, tell me something that will guarantee Paradise for me.” The Messenger of Allah, peace and blessings be upon him, said:

طِيبُ الْكَلامِ وَبَذْلُ السَّلامِ وَإِطْعَامُ الطَّعَامِ

Speak kind words, offer peace, and feed the hungry.

Source: Ṣaḥīḥ Ibn Ḥibbān 509, Grade: Sahih

Hani’ ibn Yazid reported: The Prophet, peace and blessings be upon him, said:

إِنَّ مِنْ مُوجِبَاتِ الْمَغْفِرَةِ بَذْلُ السَّلامِ وَحُسْنُ الْكَلامِ

Verily, among the deeds that must result in forgiveness are offering peace and good words.

Source: al-Mu’jam al-Kabīr 17950, Grade: Sahih

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

إِنَّ فِي الْجَنَّةِ غُرْفَةً يُرَى ظَاهِرُهَا مِنْ بَاطِنِهَا وَبَاطِنُهَا مِنْ ظَاهِرِهَا

Verily, in Paradise are rooms whose outside can be seen from inside and whose inside can be seen from outside.

Abu Musa said, “Who are they for, O Messenger of Allah?” The Prophet said:

لِمَنْ أَلَانَ الْكَلَامَ وَأَطْعَمَ الطَّعَامَ وَبَاتَ لِلَّهِ قَائِمًا وَالنَّاسُ نِيَامٌ

For those who speak mildly, feed the hungry, and spend the night standing for the sake of Allah while people sleep.

Source: Musnad Aḥmad 6436, Grade: Sahih

Ali ibn Abi Talib reported: The Prophet, peace and blessings be upon him, said:

إِنَّ فِي الْجَنَّةِ غُرَفًا تُرَى ظُهُورُهَا مِنْ بُطُونِهَا وَبُطُونُهَا مِنْ ظُهُورِهَا

Verily, in Paradise are chambers whose outside can be seen from the inside, and whose inside can be seen from the outside.

A man stood up and he said, “Who are they for, O Messenger of Allah?” The Prophet said:

لِمَنْ أَطَابَ الْكَلَامَ وَأَطْعَمَ الطَّعَامَ وَأَدَامَ الصِّيَامَ وَصَلَّى لِلَّهِ بِاللَّيْلِ وَالنَّاسُ نِيَامٌ

For those who speak kind words, feed the poor, regularly fast, and pray to Allah at night while people sleep.

Source: Sunan al-Tirmidhī 1984, Grade: Hasan

Anas reported: A man said to the Prophet, peace and blessings be upon him, “Teach me deeds that will admit me into Paradise.” The Prophet said:

أَطْعِمِ الطَّعَامَ وَأَفْشِ السَّلامَ وَأَطِبِ الْكَلامَ وَصَلِّ بِاللَّيْلِ وَالنَّاسُ نِيَامٌ تَدْخُلُ الْجَنَّةَ بِسَلامٍ

Feed the hungry, spread peace, speak kind words, and pray at night when people sleep. You will enter Paradise in peace.

Source: Musnad al-Bazzār 2497, Grade: Sahih li ghayrihi