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

الترغيب في أداء الزكاة وتأكيد وجوبها

Encouragement to pay alms (zakat) and emphasizing its obligation.

Source: al-Targhīb wal-Tarhīb 1/514

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

بُنِيَ الْإِسْلَامُ عَلَى خَمْسٍ عَلَى أَنْ يُعْبَدَ اللَّهُ وَيُكْفَرَ بِمَا دُونَهُ وَإِقَامِ الصَّلَاةِ وَإِيتَاءِ الزَّكَاةِ وَحَجِّ الْبَيْتِ وَصَوْمِ رَمَضَانَ

Islam is built upon five: to worship Allah and to disbelieve in what is worshiped besides him, to establish prayer, to give charity, to perform Hajj pilgrimage to the house, and to fast the month of Ramadan.

Source: Ṣaḥīḥ al-Bukhārī 8, Grade: Muttafaqun Alayhi

Abu Ayyub reported: A man came to the Prophet, peace and blessings be upon him, and he said, “Tell me what I can do to enter Paradise and avoid Hellfire.” The Prophet said:

تَعْبُدُ اللَّهَ لَا تُشْرِكُ بِهِ شَيْئًا وَتُقِيمُ الصَّلَاةَ وَتُؤْتِي الزَّكَاةَ وَتَصِلُ ذَا رَحِمِكَ

Worship Allah and do not associate anything with him, establish prayer, give in charity, and keep good relations with your family.

When the man turned away, the Prophet said:

إِنْ تَمَسَّكَ بِمَا أُمِرَ بِهِ دَخَلَ الْجَنَّةَ

If he adheres to what he has been commanded, then he will enter Paradise.

Source: Ṣaḥīḥ al-Bukhārī 1332, Grade: Muttafaqun Alayhi

Abu Huraira reported: A bedouin came to the Messenger of Allah, peace and blessings be upon him, and he said, “O Messenger of Allah, show me a deed by which I may enter Paradise.” The Prophet said:

تَعْبُدُ اللَّهَ لَا تُشْرِكُ بِهِ شَيْئًا وَتُقِيمُ الصَّلَاةَ الْمَكْتُوبَةَ وَتُؤَدِّي الزَّكَاةَ الْمَفْرُوضَةَ وَتَصُومُ رَمَضَانَ

Worship Allah and never associate anything with Him, establish the prescribed prayers, give the obligatory charity, and fast of the month of Ramadan.

The man said, “By Him in whose hand is my soul, I will never add anything to it, nor will I lessen anything from it.” When the man turned his back, the Prophet said, “

مَنْ سَرَّهُ أَنْ يَنْظُرَ إِلَى رَجُلٍ مِنْ أَهْلِ الْجَنَّةِ فَلْيَنْظُرْ إِلَى هَذَا

Whoever is pleased to see a man from the people of Paradise should look to him.

Source: Ṣaḥīḥ al-Bukhārī 1333, Grade: Muttafaqun Alayhi

Jarir ibn Abdullah reported:

بَايَعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى إِقَامِ الصَّلَاةِ وَإِيتَاءِ الزَّكَاةِ وَالنُّصْحِ لِكُلِّ مُسْلِمٍ

I pledged allegiance to the Messenger of Allah, peace and blessings be upon him, to establish prayer, to give charity, and to be sincere to every Muslim.

Source: Ṣaḥīḥ al-Bukhārī 57, Grade: Muttafaqun Alayhi

‘Amr ibn Murrah reported: A man came to the Prophet, peace and blessings be upon him, and he said, “O Messenger of Allah, what do you think if I testify there is no God but Allah and you are the Messenger of Allah, I perform the five prayers, I pay the obligatory alms, I fast the month of Ramadan and stand for prayer in it. Among whom will I be?” The Prophet said:

مِنَ الصِّدِّيقِينَ وَالشُّهَدَاءِ

Among the truthful and the martyrs.

Source: Ṣaḥīḥ Ibn Ḥibbān 3492, Grade: Sahih

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

خَمْسٌ مَنْ جَاءَ بِهِنَّ مَعَ إِيمَانٍ دَخَلَ الْجَنَّةَ مَنْ حَافَظَ عَلَى الصَّلَوَاتِ الْخَمْسِ عَلَى وُضُوئِهِنَّ وَرُكُوعِهِنَّ وَسُجُودِهِنَّ وَمَوَاقِيتِهِنَّ وَصَامَ رَمَضَانَ وَحَجَّ الْبَيْتَ إِنْ اسْتَطَاعَ إِلَيْهِ سَبِيلًا وَأَعْطَى الزَّكَاةَ طَيِّبَةً بِهَا نَفْسُهُ وَأَدَّى الْأَمَانَةَ

Whoever comes with five deeds, along with faith, will enter Paradise: one who preserves the five prayers, their ablution, their bowings, their prostrations, and their timings, who fasts the month of Ramadan, who performs Hajj pilgrimage to the House if he can find a way, who gives charity with a cheerful soul, and one who fulfills the trust.

Source: Sunan Abī Dāwūd 42, Grade: Hasan

Mu’adh ibn Jabal reported: I said, “O Messenger of Allah, tell me of a deed that will admit me into Paradise and keep me away from the Hellfire.” The Messenger of Allah, peace and blessings be upon him, said:

لَقَدْ سَأَلْتَنِي عَنْ عَظِيمٍ وَإِنَّهُ لَيَسِيرٌ عَلَى مَنْ يَسَّرَهُ اللَّهُ عَلَيْهِ تَعْبُدُ اللَّهَ وَلَا تُشْرِكْ بِهِ شَيْئًا وَتُقِيمُ الصَّلَاةَ وَتُؤْتِي الزَّكَاةَ وَتَصُومُ رَمَضَانَ وَتَحُجُّ الْبَيْتَ

You have asked about an enormous matter, yet it is easy upon those for whom Allah makes it easy. Worship Allah and do not associate anything with him, establish the prayer, give the charity, fast the month of Ramadan, and perform pilgrimage to the House. 

Source: Sunan al-Tirmidhī 2616, Grade: Sahih

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

ثَلَاثٌ أَحْلِفُ عَلَيْهِنَّ لَا يَجْعَلُ اللهُ عَزَّ وَجَلَّ مَنْ لَهُ سَهْمٌ فِي الْإِسْلَامِ كَمَنْ لَا سَهْمَ لَهُ وَأَسْهُمُ الْإِسْلَامِ ثَلَاثَةٌ الصَّلَاةُ وَالصَّوْمُ وَالزَّكَاةُ وَلَا يَتَوَلَّى الله عَزَّ وَجَلَّ عَبْدًا فِي الدُّنْيَا فَيُوَلِّيهِ غَيْرَهُ يَوْمَ الْقِيَامَةِ

I swear upon three of which Allah does not make one with a share in Islam like one without. The shares of Islam are three: prayer, fasting, and charity. Allah Almighty does not take a servant as an ally in this world and entrust him to another on the Day of Resurrection.

Source: Musnad Aḥmad 25121, Grade: Sahih

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

الْإِسْلَامُ ثَمَانِيَةُ أَسْهُمٍ الْإِسْلَامُ سَهْمٌ وَالصَّلَاةُ سَهْمٌ وَالزَّكَاةُ سَهْمٌ وَحَجُّ الْبَيْتِ سَهْمٌ وَالصِّيَامُ سَهْمٌ وَالْأَمْرُ بِالْمَعْرُوفِ سَهْمٌ وَالنَّهْيُ عَنِ الْمُنْكَرِ سَهْمٌ وَالْجِهَادُ فِي سَبِيلِ اللَّهِ سَهْمٌ وَقَدْ خَابَ مَنْ لَا سَهْمَ لَهُ

Islam has eight shares: Islam is a share, prayer is a share, charity is a share, Hajj pilgrimage to the House is a share, fasting is a share, enjoining good is a share, forbidding evil is a share, and jihad in the way of Allah is a share. He has failed who has a share of none.

Source: Musnad al-Bazzār 2928, Grade: Hasan li ghayrihi

Jabir reported: A man among his people said, “O Messenger of Allah, what do you think if a man pays alms on his wealth?” The Messenger of Allah, peace and blessings be upon him, said:

مَنْ أَدَّى زَكَاةَ مَالِهِ فَقَدْ ذَهَبَ عَنْهُ شَرُّهُ

Whoever pays alms on his wealth, his evil will depart from him.

Source: al-Mu’jam al-Awsaṭ 1579, Grade: Hasan li ghayrihi

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

أَقِيمُوا الصَّلَاةَ وَآتُوا الزَّكَاةَ وَحُجُّوا واعْتَمِرُوا واسْتَقِيمُوا يُسْتَقَمْ بِكُمْ

Establish prayer, give charity, perform the Hajj and Umrah pilgrimages, and be upright; your affairs will be made upright.

Source: al-Mu’jam al-Kabīr 6897, Grade: Sahih

Abdullah ibn Mu’awiyyah reported: The Prophet, peace and blessings be upon him, said:

ثَلَاثٌ مَنْ فَعَلَهُنَّ فَقَدْ طَعِمَ طَعْمَ الْإِيمَانِ مَنْ عَبَدَ اللَّهَ وَحْدَهُ وَأَنَّهُ لَا إِلَهَ إِلَّا اللَّهُ وَأَعْطَى زَكَاةَ مَالِهِ طَيِّبَةً بِهَا نَفْسُهُ رَافِدَةً عَلَيْهِ كُلَّ عَامٍ

Whoever does three deeds will taste the sweetness of faith: one who worships Allah alone, who declares there is no God but Allah, and who gives charity from his wealth each year with a cheerful and earnest soul.

Source: Sunan Abī Dāwūd 1582, Grade: Sahih

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

إِذَا أَدَّيْتَ زَكَاةَ مَالِكَ فَقَدْ قَضَيْتَ مَا عَلَيْكَ فِيهِ وَمَنْ جَمَعَ مَالًا حَرَامًا ثُمَّ تَصَدَّقَ بِهِ لَمْ يَكُنْ لَهُ فِيهِ أَجْرٌ وَكَانَ إِصْرُهُ

If you pay alms on your property, you have fulfilled your obligation. Whoever accumulates wealth unlawfully and then spends it in charity, he will not have a reward and its burden of sin is upon him.

Source: Ṣaḥīḥ Ibn Ḥibbān 3216, Grade: Hasan

Nafi’ reported: Ibn Umar, may Allah be pleased with him, said:

كُلُّ مَالٍ أَدَّيْتَ زَكَاتَهُ وَإِنْ كَانَ تَحْتَ سَبْعِ أَرَضِينَ فَلَيْسَ بِكَنْزٍ وَكُلُّ مَالٍ لَا تُؤَدِّي زَكَاتَهُ فَهُوَ كَنْزٌ وَإِنْ كَانَ ظَاهِرًا عَلَى وَجْهِ الْأَرْضِ

Every piece of property on which alms is paid, even if it were beneath the seven earths, it will never be buried. Every piece of property on which alms is not paid is buried, even if it were to lie openly on the face of the earth.

Source: al-Sunan al-Kubrá lil-Bayhaqī 7230, Grade: Sahih

Zirr ibn Hubaysh reported: A man came to Ibn Mas’ud, may Allah be pleased with him, and he said, “O Abu Abdur Rahman, which degree of Islam is best?” Ibn Mas’ud said:

الصَّلَاةُ

Prayer.

The man said, “Then what?” Ibn Mas’ud said:

الزَّكَاةُ

Charity.

The man said, “Then what?” Ibn Mas’ud said:

بِرُّ الْوَالِدَيْنِ

Righteousness to parents.

Source: al-Mu’jam al-Kabīr 9824, Grade: Hasan