As for celebrating the Mawlid, the Shari`ah proofs emphasize that it is not permissible to celebrate the Mawlid of the Messenger (peace be upon him) or anyone else. This is Bid`ah (innovation in religion), for the Messenger (peace be upon him) did not mark it or any of his RightlyGuided Caliphs, Sahabah (Companions of the Prophet) (may Allah be pleased with them) or Tabi`un (Followers, the generation after the Companions of the Prophet) who followed them in righteousness in the best centuries, were most informed of the Sunnah (whatever is reported from the Prophet), loved the Messenger (peace be upon him) most, and were keen to follow his way after him.
He who innovates things in our affairs for which there is no valid (reason) (commits sin) and these are to be rejected.
You must follow my Sunnah and that of the RightlyGuided Caliphs. Stick to and hold fast to them. Avoid novelties, for every novelty is Bid`ah and every Bid`ah is an error.
And then, the best of the speech is the Book of Allah, and the best of the guidance is the guidance given by Muhammad. And the most evil affairs are their novelties; and every Bid`ah is error. (Related by Muslim in his Sahih)
We did refer this question, i.e., celebrating the Mawlid, to the Book of Allah and found that Allah orders us to follow his Messenger (peace be upon him) in what he preached and warns us against instituting in His Religion that which He has not ordained. Allah states that He has perfected the Religion for this Ummah. This celebration was not mentioned by the Messenger (peace be upon him). Thus, it is not of the religion which Allah made perfect for us and ordered us to follow His Messenger therein.
Besides, we referred this question to the Sunnah of the Messenger of Allah and found that he (peace be upon him) did not do it nor order us to do it, nor did his Sahabah (may Allah be pleased with them). Therefore, we became sure that the Mawlid is not of the religion and is an innovated Bid`ah. It entails resembling the Jews and Christians with regard to their festivals. Consequently, it is clear to any person with the least degree of wisdom and desire to establish AlHaqq (the Truth) that celebrating the Mawlid is not of the religion of Islam. Rather, it is considered one of the innovated Bid`ahs which Allah and His Messenger ordered us to