Celebration of Mawlid An-Nabawi (the birth of Prophet Mohammad pbuh).

Note: We are referring here to specifying a certain day where certain actions are done in celebration. Of course, every Muslim celebrates Prophet Mohammad (pbuh) every day of the year by abiding by his commands and staying away from anything he forbid, and by following his Sunnah in every way we can.

First of all it must be known that Prophet Mohammad (pbuh) never celebrated his birth or allowed others to celebrate it during his life. It must also be known that the Sahaba, and the rightly guided Khulafa', and the followers of the sahaba, and the salaf (early generations of Muslims) all never celebrated the birth of the Prophet.

It must also be known that as Muslims, all our religious actions must come from Allah (swt) and His Messenger. Anything else in matters or worship is considered to be "bid'ah", and it is not allowed. Therefore, it must be clear to all Muslims that considering the celebration of the birth day of the Prophet an act of worship is not allowed, because in that case it is a bid'ah and it becomes haram.

However, if Muslims take the opportunity to mention the Seerah and history of the Prophet (pbuh), and to remind people to follow the Sunnah, then there is no harm in that as long as it does not become a religious obligation or an act of worship. In addition, the teaching of the Seerah and the Sunnah should not be confined to a certain period, but must be continuous throughout the year and at all times.

http://www.al-islami.com/islam/common_mistakes.php?p=7