Yahweh has "appointments" at which Israel "rehearses" prophetic events.
Yahweh told Israel that the month during which Passover fell was to be the first month on their calendar. That is the month of Aviv, which means the time when the ears of barley begin to ripen. Passover comes on the 14th of the month (though the lamb was selected on the 10th). The feast of unleavened bread begins at sundown and lasts seven days. The day after the Sabbath that follows Passover is the Firstfruits of the Barley Harvest,which begins the counting of seven full weeks until Shavuoth (the feast of "weeks").

Why is this important? First of all, because Yahweh said so, but the relevance becomes more obvious when we see that each of these days is called an "appointment" (Hebrew, mo'ed). Why? Because Yahweh would in some way meet with Israel in a special way on these days. The gates in the Temple were only open on the Sabbath and Festivals.

But when we look at Yahshua's life, we see that something significant happened on each of these very days. His crucifixion was on Passover, and since it was just after the following Sabbath that His resurrection was discovered, we know that the day He took His blood to the heavenly altar to atone for us was on the feast of Firstfruits--the very title Paul applies to Yahshua in 1 Corinthians 15. On the 40th of the 49 days of counting, He ascended into heaven. Shavuoth is the same as Pentecost (which means "50" in Greek), the day the Holy Spirit fell in a special way. It is significant that by Jewish tradition, it was on Shavuoth that the ten commandments were given, and we read that 3,000 people fell in one day for the sin regarding the golden calf. Acts 2 tells us that 3,000 were added on that "Pentecost" after Yahshua's resurrection--a repair of this breach!

But that's not all. There is a second cluster of Festivals that come in the fall of the year: Yom Teru'ah (a.k.a. Rosh haShanah) on the first of the 7th month; Yom Kippur on the 10th; and Sukkoth (booths, when we live in open, temporary structures) from the 15th to the 21st. By tradition, Yom Teru'ah (the Feast of Trumpet-blasts or an awakening shout) has been associated with the resurrection of the dead. And indeed, 1 Thess. 4 tells us that the dead will rise with a trumpet and a shout!

Are we beginning to see a pattern? If Yahshua fulfilled each of the first set of feasts on their very day at His first coming, might He return for those who have died "in Him" on Yom Teruah? "No man knows the hour or day"--and indeed this is the only festival of which we cannot tell which day it will fall, because it comes on the New Moon, which is not proclaimed until it is actually sighted.

Yom Kippur (the Day of Atonement) correlates prophetically to the Day of Judgment, and Sukkoth is both a reminder of the temporary dwelling in the wilderness and a picture of the thousand-year Messianic Kingdom, when we will dwell in safety even without walls. An eighth day has been tacked on after the seven to extend the feast longer, which depicts the New Heaven and New Earth. The "eighth day", the day a baby is circumcised, represents a new beginning--the next round after one Sabbatical cycle.

Which leads to an interesting theory: Sukkoth is called the "Season of Our Joy" and includes sacrifices for all nations, and the angels proclaimed Yahshua's birht as "good news of great joy to all people". Would Caesar Augustus' census really fill Bethlehem to overflowing if not everyone came all at one time? What if the reason Bethlehem was so fill was that there was a spillover of pilgrims who came for the feast and could not all fit in Jerusalem? This was a common occurrence. And the Hebrew word for stable is indeed "sukkah" (the singular form of "sukkoth"), as we see in Genesis 33:17). One traditional regulation for a sukkah is that it have enough of a gap in the all-natural roofing that one can see stars through it.

David set up a schedule of 24 "courses" when the Levites would serve in the Temple for two weeks each throughout the year. We are told which of these courses John the Baptist's father was of, so we have two possible times in the year when he could have served. One of them brings the birth of John to right at Passover--the very time Jews always set a place for Elijah (Eliyahu). The angel prophesied that John (Yochanan) would come "in the spirit and power of Elijah". We know that John was six months older than Yahshua. If John was born at Passover, then indeed, Yahshua would have to be born at Sukkoth--exactly six months later!

So there's no need for a half-biblical, half-pagan "Christmas". If we need such a thing, we already have a pure, prescribed festival at the time of Yahshua's birth. Why not stick with what's trustworthy and sure?

The Festivals are part of the Gospel, because right after Nahum says, "How beautiful on the mountains are the feet of him who brings good news", he urges Judah not to forget to "keep the feasts!" Paul specifically tells Renewed Covenant believers to keep Passover, and Yahshua said He would again celebrate that feast with us upon His return.

Don't we want to be in practice so we know what's going on when that time comes?