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]

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]