In the Name of Allah, the Gracious, the Merciful
Imam al-Nawawi records in his book Meadows of the Righteous:
باب فضل الحب في الله والحث عَلَيهِ وإعلام الرجل من يحبه أنه يحبه وماذا يقول لَهُ إِذَا أعلمه
Chapter on the virtue of love for the sake of Allah, encouragement to it, and a man notifying those whom he loves that he loves them and what to say when he is told so.
Source: Riyāḍ al-Ṣāliḥīn 1/136
Anas ibn Malik reported: The Messenger of Allah, peace and blessings be upon him, said:
ثَلاَثٌ مَنْ كُنَّ فِيهِ وَجَدَ حَلاَوَةَ الإِيمَانِ مَنْ كَانَ اللَّهُ وَرَسُولُهُ أَحَبَّ إِلَيْهِ مِمَّا سِوَاهُمَا وَمَنْ أَحَبَّ عَبْدًا لاَ يُحِبُّهُ إِلاَّ لِلَّهِ وَمَنْ يَكْرَهُ أَنْ يَعُودَ فِي الْكُفْرِ بَعْدَ إِذْ أَنْقَذَهُ اللَّهُ كَمَا يَكْرَهُ أَنْ يُلْقَى فِي النَّارِ
Whoever has three traits within himself will find the sweetness of faith: one who loves Allah and His Messenger more than anything else, one who loves a servant only for the sake of Allah, and one who hates to turn back to unbelief after Allah has saved him, just as he hates to be thrown into the fire.
Source: Ṣaḥīḥ al-Bukhārī 21, Grade: Muttafaqun Alayhi
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
سَبْعَةٌ يُظِلُّهُمْ اللَّهُ فِي ظِلِّهِ يَوْمَ لَا ظِلَّ إِلَّا ظِلُّهُ الْإِمَامُ الْعَادِلُ وَشَابٌّ نَشَأَ بِعِبَادَةِ اللَّهِ وَرَجُلٌ قَلْبُهُ مُعَلَّقٌ فِي الْمَسَاجِدِ وَرَجُلَانِ تَحَابَّا فِي اللَّهِ اجْتَمَعَا عَلَيْهِ وَتَفَرَّقَا عَلَيْهِ وَرَجُلٌ دَعَتْهُ امْرَأَةٌ ذَاتُ مَنْصِبٍ وَجَمَالٍ فَقَالَ إِنِّي أَخَافُ اللَّهَ وَرَجُلٌ تَصَدَّقَ بِصَدَقَةٍ فَأَخْفَاهَا حَتَّى لَا تَعْلَمَ يَمِينُهُ مَا تُنْفِقُ شِمَالُهُ وَرَجُلٌ ذَكَرَ اللَّهَ خَالِيًا فَفَاضَتْ عَيْنَاهُ
There are seven whom Allah will shade on a day when there is no shade but his. They are a just ruler, a youth who grew up in the worship of Allah, one whose heart is attached to the mosques, two who love each other, meet each other, and depart from each other for the sake of Allah, a man who is tempted by a beautiful woman of high status but he rejects her, saying , ‘I fear Allah,’ one spends in charity and conceals it such that his right hand does not know what his left hand has given, and one who remembered Allah in private and he wept.
Source: Ṣaḥīḥ al-Bukhārī 660, Grade: Muttafaqun Alayhi
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
إِنَّ اللَّهَ يَقُولُ يَوْمَ الْقِيَامَةِ أَيْنَ الْمُتَحَابُّونَ بِجَلَالِي الْيَوْمَ أُظِلُّهُمْ فِي ظِلِّي يَوْمَ لَا ظِلَّ إِلَّا ظِلِّي
Verily, Allah will say on the Day of Resurrection: Where are those who love each other for the sake of My glory? Today, I will shelter them in My shade on a day when there is no shade but Mine.
Source: Ṣaḥīḥ Muslim 2566, Grade: Sahih
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
لَا تَدْخُلُونَ الْجَنَّةَ حَتَّى تُؤْمِنُوا وَلَا تُؤْمِنُوا حَتَّى تَحَابُّوا أَوَلَا أَدُلُّكُمْ عَلَى شَيْءٍ إِذَا فَعَلْتُمُوهُ تَحَابَبْتُمْ أَفْشُوا السَّلَامَ بَيْنَكُمْ
You will not enter Paradise until you have faith and you will not have faith until you love each other. Shall I show you something that, if you did, you would love each other? Spread peace between yourselves.
Source: Ṣaḥīḥ Muslim 54, Grade: Sahih
In another narration, the Prophet said:
وَالَّذِي نَفْسِي بِيَدِهِ لا تَدْخُلُوا الْجَنَّةَ حَتَّى تُسْلِمُوا وَلا تُسْلِمُوا حَتَّى تَحَابُّوا وَأَفْشُوا السَّلامَ تَحَابُّوا وَإِيَّاكُمْ وَالْبُغْضَةَ فَإِنَّهَا هِيَ الْحَالِقَةُ لا أَقُولُ لَكُمْ تَحْلِقُ الشَّعْرَ وَلَكِنْ تَحْلِقُ الدِّينَ
By the One in whose hand is my soul, you will not enter Paradise until you submit to Allah, and you will not submit until you love one another. Spread peace and you will love one another. Beware of hatred, for it is the razor. I do not say that it shaves hair, but rather it shaves away the religion.
Source: al-Adab al-Mufrad lil-Bukhārī 260, Grade: Hasan
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
رَجُلًا زَارَ أَخًا لَهُ فِي قَرْيَةٍ أُخْرَى فَأَرْصَدَ اللَّهُ لَهُ عَلَى مَدْرَجَتِهِ مَلَكًا فَلَمَّا أَتَى عَلَيْهِ قَالَ أَيْنَ تُرِيدُ قَالَ أُرِيدُ أَخًا لِي فِي هَذِهِ الْقَرْيَةِ قَالَ هَلْ لَكَ عَلَيْهِ مِنْ نِعْمَةٍ تَرُبُّهَا قَالَ لَا غَيْرَ أَنِّي أَحْبَبْتُهُ فِي اللَّهِ عَزَّ وَجَلَّ قَالَ فَإِنِّي رَسُولُ اللَّهِ إِلَيْكَ بِأَنَّ اللَّهَ قَدْ أَحَبَّكَ كَمَا أَحْبَبْتَهُ فِيهِ
A man set out to visit his brother from another town, so Allah sent an angel to watch over his steps. When the angel came to him, he said: Where are you going? The man said: I am visiting a brother of mine in this town. The angel said: Do you have a favor over him to be repaid? He said: No, only that I love him for the sake of Allah Almighty. The angel said: I am a messenger from Allah to tell you that Allah loves you just as you love him.
Source: Ṣaḥīḥ Muslim 2567, Grade: Sahih
Al-Bara’ reported: The Messenger of Allah, peace and blessings be upon him, said about the Ansar:
لَا يُحِبُّهُمْ يعنى الْأَنْصَار إِلَّا مُؤْمِنٌ وَلَا يُبْغِضُهُمْ إِلَّا مُنَافِقٌ فَمَنْ أَحَبَّهُمْ أَحَبَّهُ اللَّهُ وَمَنْ أَبْغَضَهُمْ أَبْغَضَهُ اللَّهُ
None loves the Ansar but a believer, and none hates them but a hypocrite. Whoever loves them, Allah will love him. Whoever hates them, Allah will hate him.
Source: Ṣaḥīḥ al-Bukhārī 3783, Grade: Muttafaqun Alayhi
Mu’adh ibn Jabal reported: The Messenger of Allah, peace and blessings be upon him, said:
قَالَ اللَّهُ عَزَّ وَجَلَّ الْمُتَحَابُّونَ فِي جَلَالِي لَهُمْ مَنَابِرُ مِنْ نُورٍ يَغْبِطُهُمْ النَّبِيُّونَ وَالشُّهَدَاءُ
Allah Almighty said: Those who love each other for the sake of My glory will be upon pulpits of light, admired by the prophets and the martyrs.
Source: Sunan al-Tirmidhī 2390, Grade: Sahih
In another narration, the Prophet said:
قَالَ اللَّهُ عَزَّ وَجَلَّ وَجَبَتْ مَحَبَّتِي لِلْمُتَحَابِّينَ فِيَّ وَالْمُتَجَالِسِينَ فِيَّ وَالْمُتَزَاوِرِينَ فِيَّ وَالْمُتَبَاذِلِينَ فِيَّ
Allah Almighty said: My love is assured for those who love each other for My sake, who sit together for My sake, who visit each other for My sake, and who spend on each other for My sake.
Source: Musnad Aḥmad 22030, Grade: Sahih
And in another narration, the Prophet said:
عَنِ اللَّهِ عَزَّ وَجَلَّ حَقَّتْ مَحَبَّتِي لِلْمُتَحَابِّينَ فِيَّ وَحَقَّتْ مَحَبَّتِي لِلْمُتَوَاصِلِينَ فِيَّ وَحَقَّتْ مَحَبَّتِي لِلْمُتَزَاوِرِينَ فِيَّ وَحَقَّتْ مَحَبَّتِي لِلْمُتَبَاذِلِينَ فِيَّ
Allah Almighty said: My love is a right upon those who love each other for My sake. My love is a right upon those who maintain relations for My sake. My love is a right upon those who visit each other for My sake. My love is a right upon those who spend on each other for My sake.
Source: Musnad al-Bazzār 2697, Grade: Sahih
And in another narration, the Prophet said:
قَالَ اللَّهُ تَعَالَى حَقَّتْ مَحَبَّتِي لِلَّذِينَ يَتَصَادَقُونَ مِنْ أَجْلِي وَحَقَّتْ مَحَبَّتِي لِلَّذِينَ يَتَنَاصَرُونَ مِنْ أَجْلِي
Allah Almighty said: My love is a right upon those who befriend each other for my sake. My love is a right upon those who defend each other for my sake.
Source: al-Mu’jam al-Ṣaghīr lil-Ṭabarānī 1095, Grade: Sahih
Al-Miqdam ibn Ma’dikarib reported: The Messenger of Allah, peace and blessings be upon him, said:
إِذَا أَحَبَّ أَحَدُكُمْ أَخَاهُ فَلْيُعْلِمْهُ إِيَّاهُ
When one of you loves his brother, let him know.
Source: Sunan al-Tirmidhī 2392, Grade: Sahih
Anas ibn Malik reported: A man was with the Messenger of Allah, peace and blessings be upon him, when another man passed by and he said, “O Messenger of Allah, I love this man.” The Prophet said:
أَعْلَمْتَهُ
Have you told him?
He said no. The Prophet said:
أَعْلِمْهُ
Tell him.
He went to the man and he said to him, “I love you for the sake of Allah.” The other man replied:
أَحَبَّكَ الَّذِي أَحْبَبْتَنِي لَهُ
May Allah, for whose sake you love me, also love you.
Source: Sunan Abī Dāwūd 5125, Grade: Sahih
Mu’adh ibn Jabal reported: The Messenger of Allah, peace and blessings be upon him, took me by the hand and he said:
يَا مُعَاذُ وَاللَّهِ إِنِّي لَأُحِبُّكَ وَاللَّهِ إِنِّي لَأُحِبُّكَ أُوصِيكَ يَا مُعَاذُ لَا تَدَعَنَّ فِي دُبُرِ كُلِّ صَلَاةٍ تَقُولُ اللَّهُمَّ أَعِنِّي عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ
O Mu’adh, I swear by Allah that I love you. I swear by Allah that I love you. O Mu’adh, I advise you not to forget supplicating at the end of every prayer, saying: O Allah, help me to remember You, to give thanks to You, and to worship You in the best manner.
Source: Sunan Abu Dawud 1522, Grade: Sahih
Success comes from Allah, and Allah knows best.