The Prophet's Birthday

The Celebration of Mawlid was introduced by the ruler of Irbil; Muzaffar ad-Din ibn Zain al-Din. He was assisted by Abdul Khattab Umar ibn Dihya, who composed a book al-Tanwir fi Maulid al-Siraj al-Munir, in an attempt to justify Mawlid celebrations. [Ibn Katheer, al-Bidaya wa al-Nihaya, Vol.I3 pp.144-146]

Ibn Katheer has reported on the authority of al-Sabt about Ibn Dihya: "He used to defame the Muslims and belittle them. He would make additions in his report and exaggerate. So, the people gave up narrating traditions from him and falsified him. …" [Ibn Kathir, al-Bidaya wa al-Nihaya, Vol.I3 pp.144-146]

Celebrating Mawlid (the Prophet's assumed birthday) has no origin from the Book and Sunnah, rather it is an innovation from the one, who was known for making additions and exaggerations in the Religion. A practice that came into existence 600 years, way past the time of the Messenger of Allah (sallallahu alaihi wa-sallam), his Companions (radhi allahu anhu) and their followers, can never be a part of Islam because the religion of Islam is based upon the revelation from Allah. To introduce the celebration of Mawlid in the religion, one will have to break the seal of Allah, Who said: "This day I have perfected your religion for you, completed my Favor upon you and have chosen for you Islam as your religion." [Soorah al-Maidah (5):3]

Allah's Messenger (sallallahu alaihi wa-sallam) was sent as a guide and warner. Allah says: "We have not sent you, but as a universal (Messenger) to men, giving them glad tidings, and warning them (against sins)" [as-Saba (33): 28]

And he (sallallahu alaihi wa-sallam) said: "There is nothing that will take you closer to Paradise but that I have enjoined it upon you, and there is nothing that will take you closer to Hell but that I have warned you from it." [Musnad ash-Shafa'ee and others]

The Messenger of Allah (sallallahu alaihi wa-sallam) never celebrated his birthday, nor did he instruct or order his Companions (radhi allahu anhu) to do so. If Mawlid was an expression of love or an act of drawing closer to Allah, then he (sallallahu alaihi wa-sallam) would have certainly guided his Companions (radhi allahu anhu) to it. Thus, Mawlid is neither an act of righteousness, nor an expression of love for the Messenger of Allah (sallallahu alaihi wa-sallam).

source: Who Really Loves the Messenger of Allah - In Light of Mawlid celebrations - From As-Sunnah Bimonthly Islamic Newsletter