Why is Jesus Birth celebrated by Date 25 Dec, Where as Death by Day (Friday) ?

It is not a mix up. Jesus was killed just before sunset of the Jewish Passover. The Jewish Passover comes on the 14th of Nisan according to the Jewish calendar. Because we go by the Roman calendar, the days do not coincide. Each year the date must be adjusted to get close to the Jewish calendar. Most years it is pretty close except when there is an extra month in the Jewish calendar. You can learn more about this by going to this article on Easter: http://en.wikipedia.org/wiki/Easter As for December 25, for Christ's birth. The Bible does not give us a date of Jesus' birth. This date was picked to go along with the winter solstice that was celebrated by the non Christians during the time of Constantine. If you really want to know about the days God appointed, check into the Jewish Holy Day (seven of them) to understand more of what the Bible tells us to celebrate. I am not Jewish but this is a bit of what I have learned in my 30+ years of Christianity. It is good that you ask questions as most do not. Here is one, have you ever wondered why Easter has rabbits and eggs since rabbits do not lay eggs. What is the connection?