Chrsitmas is one of the lightest christian celebrations. Then we celebrate the Saviour's birth - Jesus Christ.
According to the Gospel the birth happened in Vitleem, in Judaea. Prophet Danail fortold Christ would appear 490 years after the Refund of Jerusalem temple. With the oncoming of the indicated time all hopes of Judean turned on the coming Messiah. A little bit before the birth, His mother, Maria, together with Joseph go to Vitleem. They couldn't find a place in the inn and they were forced to take shelter in a cave out of the city, where the shepherds shut the sheep. There Maria bore her Son, put a diaper on and laid in cribs, where there were tied up a dickey and a ox. With their breath they warmed the divine new born Child.
Several are the reasons Christ was born on Earth. First - He was born to die for people's sins. Second - to adoptthe people and carry out the God's law. Except that He was brought into the world to perform God's will and destroy the evil's acts.
We should rationalize our celebration on this feast and really to remind the great God act and try to be better.