There is historical proof as well as scriptural proof.
A noted advocate of the December 25th date was John Chrysostom (c. 347-407), a humble and caring man, perhaps best known for his writings on the Bible and the Christian faith. He was also an eloquent preacher in the city of Constantinople, where his sermons became a stronger attraction for people than the shows of the amphitheater. Through his ministry many souls came to Christ-from among heretics, pagans, and Jews.
He was not without his enemies, however, and suffered times of persecution, including his church being burned down. illtimately the Emperor Arcadius ordered his banishment to an inhospitable region, the desert of Pityos. But while being taken there, Chrysostom died in his 60th year. It is reported that with his last words he was praising the Lord!
Chrysostom claimed the December 25th date was supported by the actual census/tax records of the Holy Family when they registered in Bethlehem. We have no way to prove if those records were still in existence, or were authentic, but Chrysostom was not the only one who referred to them.
Justin Martyr (100-165), in his noted Apology-a detailed explanation of the Christian faith addressed to the Emperor Marcus Aurelius-stated that Jesus was born at Bethlehem ''as you can ascertain also from the registers of the taxing" (Apol. I, 34). Tertullian (160-250) spoke of "the census of Augustus-that most faithful witness of the Lord's nativity, kept in the archives of Rome" (Against Marcion, Bk. 4, 7). When Cyril of Jerusalem (348- 386) asked Julius to assign the true date of Christ's birth "from census documents brought by Titus to Rome," Julius assigned December 25th.
Chrysostom taught that it was on the day of Atonement that Zacharias received the angelic announcement that he would have a son. This would place the conception of John in late September, and so the conception of Christ (which was six months later) in March, leading to a December birth!
According to rabbinical tradition, when the temple was destroyed in 70 A.D., the priestly course of Jehoiarib was serving. If the order of priestly service was unbroken through all those 70 years, it has been calculated that the course of Abijah, to which Zacharias belonged, would have been serving during the first week of October. This would be only slightly later than Chrysostom's position, but one which would still allow for Christ's conception to have been in March and his birth in December.
It should be carefully noted, however, that numerous arguments have been based on when Zacharias served. None are conclusive, since all must assume certain things:
Did the priestly courses start at the beginning of each year, or did they function as a continuous week by week cycle? Was this cycle interrupted during the annual feasts? Did all priests serve then, with the order of courses continuing thereafter? When the Jews added a month, every three years or so (to bring their lunar calendar into alignment with the solar year), how did this affect the timing of the courses? Did they always follow a totally uniform and unchanging policy from generation to generation, or were there variables? Our purpose here is not to argue for one date over another, so we need not get hung up on details.
THE CHRIST FROM BIRTH
There was a sect, the Gnostics, who believed Jesus of Nazareth became the "Christ" at his baptism, that this was when God was "manifested" in the flesh. Eventually, through the influence of Valentinus, January 6 was set aside to honor this event, called "Epiphany" (from the Greek epiphaneia, meaning manifestation).
There were others who began to observe Epiphany on this date also, but they believed (correctly) that Jesus was the Christ from his birth. However, since Jesus' baptism occurred on or near the anniversary of his birth (Lk. 3:23), it seemed more fitting for them to observe January 6th in honor of his birth. This may have even served to counter the false teaching of the Gnostics, emphasizing by this observance, that he had an actual birth as the Christ. If so, setting aside a day to honor his birth did not stem from some ulterior motive. The Armenian Church still observes January 6th.
Was there a feasible basis for January 6th as the date of Christ's birth, and subsequent baptism 30 years later on this date? Was this based on some then-extant records? I don't know. Centuries ago there were disputes as to whether January 6th or December 25th was the correct date, with large groups of people favoring one or the other. But in either case, these two dates only a few days apart are both in winter!
Would winter be a feasible time for the baptism of Jesus? I know of no reason why not at least the winter weather would not have interfered. The very low elevation of the Jordan where Jesus was baptized-near the Dead Sea, which is the lowest spot on earth-enjoys a very mild winter climate.
What about travel for Joseph and Mary from Nazareth to Bethlehem in winter? It is very possible they would have chosen the route through the Jordan Valley. If so, a large percentage of the trip would have been below sea level, thus providing protection from cold weather, even in December. (The Jordan Valley runs between the Sea of Galilee at 689 feet below sea level, to the Dead Sea at 1,306 feet below sea level.)
Would winter have been the time for people like Joseph and Mary to be taxed? It must have been in winter, for only then was field labor suspended! Shepherds in the field at winter, yes. It has been often stated that shepherds in that, part of the world did not abide in the field during the middle of winter, that by October 15th they would have brought their flocks home-thus ruling out December as the time of Christ's birth. But this is far from conclusive. There may have been exceptions. That some shepherds did face cold weather may be seen in Jacob's complaint to Laban, that he had suffered from frost by night (Gen. 31:40).
In his highly regarded and scholarly volumes, The Life and Times of Jesus the Messiah, Alfred Edersheim says about December 25th: "There is no adequate reason for questioning the historical accuracy of this date. The objections generally made rest on grounds, which seem to me historically untenable." Though various writers have quoted Lightfoot about flocks not lying out during the winter months, this was not true of all flocks. He cites ancient Jewish sources to the effect that there are flocks that "remain in the open alike in the hottest days and in the rainy season i.e. all the year round" (The Life and Times of Jesus the Messiah, Bk.2, p.186),
When Luke mentioned shepherds abiding in the field, did he seek to convey what time of year it was, was not or might these words suggest something different: that these shepherds were very poor, living in the field with their flock? They may have been without shelter for their flock or houses for themselves regardless of what season it was.
It is very possible they were this poor. If so, there is a beautiful contrast between the shepherds and the wise men who were, apparently, very rich. Both groups came to worship Jesus while he was an infant, a lovely example of how the message of Christ is for all people, rich or poor.