"It is narrated by Mu‘ādh bin Jabal that he heard the Messenger of Allāh (صلى الله عليه وآله وسلم) saying:

   Allāh the Exalted and Almighty said: ‘My love has been made obligatory for those two persons who love each other on My count and spend time together for My sake, and see each other for My sake and give money to each other generously for My sake.’"

This sahīh (sound) hadīth narrated by Mālik bin Anas in al-Muwattā, b. of sha‘ar (hair) ch.5 (2:954#16), and Ibn ‘Abd-ul-Barr said its chain is good. Ahmad bin Hambal also transmitted it in his Musnad (5:233); Hākim in al-Mustadrak (4:169), who graded it sahīh, and also confirmed by Dhahabī; Baghawī in Sharh-us-sunnah, (13:49-50#3463); Khatīb Tabrīzī in Mishkāt-ul-masābīh, b. of ādāb (good manners) ch.16 (3:75#5011). [src: Ch3 of Beseeching for Help, Tahir-ul-Qadri]

Allah Most High says: "He who is hostile to a friend of Mine I declare war against. My slave approaches Me with nothing more beloved to Me than what I have made obligatory upon him, and My slave keeps drawing nearer to Me with voluntary works until I love him. And when I love him, I am his hearing with which he hears, his sight with which he sees, his hand with which he seizes, and his foot with which he walks. If he asks me, I will surely give to him, and if he seeks refuge in Me, I will surely protect him"

(Sahih Bukhari - Fath al-Bari, 11.340 41, hadith 6502) [src: suhba.org]

Narrated by Ubayy ibn Ka'b (Radi Allah Ta'lah Anhu): "I said: Allah's Messenger (Sal-allahu-aleihi-wasallam), I invoke blessings upon you very frequently. How much of my supplication should I devote to you. He said: As much as you like. I said: May it be a quarter? He said: As much as you like, but if you increase it, it will be good for you. I said: May it be a half? He said: As much as you like, but if you increase it, it will be good for you. I said: May it be two thirds? He said: As much as you like but if you make an increase in it, it will be better. I said: May I devote the whole of my supplication to you (that I make in my prayer)? Thereupon he said: In that case it will take care of you and your sins would be expiated."

Tirmidhi transmitted it. Hadith No. 929 of Mishkat al-Masabih. [src: road-to-heaven.com]

It is narrated by ‘Umar bin al-Khattāb that the Prophet (صلى الله عليه وآله وسلم) said:

"Among Allāh’s servants there are some who are neither prophets nor martyrs but on the Day of Judgement the prophets and the martyrs will envy their grades. The Companions asked: ‘O Messenger of Allāh, tell us, who are those people?’ He replied: ‘those are the people who love one another on Allāh’s count. They are neither related to one another nor do they have any property to exchange. I swear on Allāh that they will have faces of light,they will be on pulpits of light. They will not have any fear when others will be afraid, they will not have any grief when others will be aggrieved.’ Then he recited the verse: Beware! No doubt, there is no fear for the friends of Allāh nor shall they be sad and sorrowful. "

[Qur’ān (Yūnus, Jonah) 10:62.]

Abū Dāwūd, Sunan, b. of ijārah (wages) 3:288 (#3527); Bayhaqī, Shu‘ab-ul-īmān, (6:486#8998,8999); Khatīb Tabrīzī, Mishkāt-ul-masābīh, b. of adab (good manners) ch.16 (3:75-6#5012).  [src: Ch3 of Beseeching for Help, Tahir-ul-Qadri]