Though the birth of Yah'shua the Messiah (Jesus Christ) was one of the most important of a cluster of key salvation-defining events in earth's long and painful history, it's celebration is nowhere commanded in the Messianic Scriptures (New Testament) and is not therefore a part of the cycle of non-subtractable or non-addable festivals of Messianic (Christian) Israel mandated by Elohim (God) for the corporate Community of Faith.
Christmas, like Easter and a whole host of other traditions that have developed in Christendom over the centuries, is pagan in origin. Communists, nazis, atheists, Wiccans, Satanists and the adherents of other non-Christian religions have, accordingly, had no problem celebrating this winter solstice festival, with minor modifications. Even secular Jews have modified their equally pagan and falsified Hanukkah festival by incorporating Christmas elements into it.
The famous and highly respected scholar, Alexander Hislop, wrote:
The very first post-Diluvian (Flood) counterfeit Messiah was Nimrod (Gen.10:9), the founder and dictator of the first city (Nineveh), who established himself as a deliverer or saviour and claimed to be the 'incarnate god'. After his untimely death, his mother, the witch Semiramis, with whom he had had an incestuous relationship, claimed (under the influence of Satan) to have had a miraculous conception and maintained that her 'husband-son' had been reincarnated as the god Tammuz, meaning 'branch'. She was thereafter worshipped as the 'mother-goddess' (madonna) and amongst her titles was that of 'queen of heaven'. Thus was born the ancient Babylonian mystery religion, from which all post-flood pagan ideas and corruptions of the emet (truth) can be traced, including 'Christmas'.
"That Christmas was originally a pagan festival is beyond all doubt. The time of the year, the ceremonies with which it is celebrated, prove its origin. In Egypt, the son of Isis, the Egyptian title for the queen of heaven, was born at this very time, about the time of the winter solstice. The very name by which Christmas is popularly known among ourselves - Yule day - proves at once its pagan and Babylonian origin. 'Yule' is the Chaldee name for 'infant', or 'little child'; and as the 25th December was referred to by Anglo-Saxon ancestors as the 'Yule-day' or 'the child's day', and the night that preceded it, 'Mother night', long before they came in contact with Christianity; that sufficiently proves its real character. Far and wide in the realms of paganism was this birthday observed" (The Two Babylons)
Though superficially resembling the story of the biblical account of the conception and birth of the true Messiah, Yah'shua (Jesus), and highly dressed up to give it a Christian flavouring with beautiful carols, 'good will too all men', and the like, the Christmas celebration is, at core, the celebration of Semiramis (the semi-deified co-Redemptrix Catholic Mary, in reality the demoness Morena) and Nimrod - the Witch and Anti-messiah, respectively. Needless to say such observances are strictly forbidden by Yahweh, El Elyon (the Most High God), who will not be mocked.
The proto-Catholic Church openly admitted from the earliest times that it ditched Yahweh's divine moedim or appointments and replaced them with ancient, Babylonian-derived Roman pagan observances. Tertullian, writing in 230 AD, said:
Given the satanic background of these pagan practices (minus the Christian 'additions'), it is little wonder that Christmas is still held in high esteem even in many of those societies that once persecuted - and still do persecute - Christians. Little wonder also that it has come to be viewed as the chief of the Catholic-originated festivals in Christendom, being practiced on 25 December each year with equal fervour by Catholics, Eastern Orthodox (on 6 January), Protestants, Mormons, Seventh Day Adventists and others.
"By us (Roman Christians) who are strangers to Sabbaths, new moons, and festivals, once acceptable to God (sic), the Saturnalia, the feasts of January, the Brumalia and Matronalia are now fragmented, with gifts being carried to and fro."
The many articles on this page will give you a thorough grounding on both the pagan tradition that has tried to pass itself off as authentically celebrating the birth of the true Messiah as well as the biblical teaching of the nature and timing of the true birth, which Messianic Evangelicals maintain was in the spring during the Passover Season. Most (though by no means all) messianics, for their own reasons (which are discussed in some of the articles), tend to favour an autumn/fall birth, though there is no concensus as to the exact day or during which festival the birth actually took place.
Though it is not official, because it is not a divine moed (appointment), many Messianic Evangelicals celebrate Messiah's birth at Aviv 1, the 'month of blossoms', the biblical new year in the spring. One of the most prominent Messianic Jewish teachers of our time, Rabbi Jonathan Cahn, author of the best selling book, The Harbinger, actually believes the birth took place on Aviv 1 itself.
For the founder of NCAY, the discovery and exposure of the 'Christmas lie' was one of the initial catalysts that led to the Messianic Evangelical restoration as represented by the NCCG.ORG website. You can read about this, and much more, on this Christmas sub-site.