Muslim narrated in his Sahih from Abu Hurairah (:ra:) that the Messenger of Allah (:saws:) said "he who invokes blessings on me once, Allah sends ten blessings upon him."
Al-Nasa’i narrated in 'Invocations of the day and night’, from ‘Umar bin Dinar (:ra:) that the Prophet (:saws:) said "he of my community who invokes blessings upon me sincerely, Allah will bless him ten fold and raise him ten degrees, and he will have written for him ten good deeds, and erased from his record ten bad deeds."
Tirmidhi narrated that ‘Umar ibn al-Khattab (:ra:) said "Verily, supplications are stalled between the heavens and the earth, and are not lifted up until the supplicant invokes blessings upon the Prophet (:saws:)."
Tirmidhi related from Abdullah bin Mas’ud (:ra:) that the Messenger of Allah (:saws:) said "the closest people to me on the Day of Resurrection will be those who invoked the most blessings upon me."
Tirmidhi narrated from ‘Amir bin Rani’ah (:ra:) that the Prophet (:saws:) said "he who invokes blessings upon me, the Angels send blessings upon him equal to that which he invoked, so let the worshiper invoke some, or increase upon that."
Source: Virtues of Durood