We rabbis often say that Hanukkah and Christmas have nothing in common except for the coincidence of a December date. I am no longer persuaded of that truism.
In America, we love our birthdays. We eat cake, blow out candles, make wishes, receive presents, read corny cards, and generally indulge ourselves.
It was not always so. In the Bible, only the non-Jew, Pharaoh, has his birthday mentioned, although its date was not recorded—in Genesis 40:20. Pharaoh marked his birthday by pardoning the butler, but executing the baker. Some celebration— The baker would have preferred to have created the cake out of which the dancing girl could spring, but one didn’t get to be Pharaoh without being schooled in cruelty.
By contrast, our illustrious biblical ancestors’ birthdays are not recorded. It is a midrash, not a Bible verse, that Moses was born on 7 Adar (because of another midrash, that he died on 7 Adar, and the hope that he lived exactly 120 years, hence dying on his birthday). Abraham? Jacob? David? None have birthdays recorded. For that matter, since Jewish authors stand behind the Gospel traditions, it is not at all surprising that the birth date of Jesus, son of Joseph and Mary, is unrecorded in the New Testament. So why December 25, for that most famous Jewish boy? And why is this of interest for the date of Hanukkah?
The earliest account of Hanukkah, the apocryphal book of First Maccabbees, tells us clearly that the Greek tyrant Antiochus began offering pagan sacrifices upon the illicit altar he had erected in the Temple of Jerusalem on the 25th day of Kislev. (I Macc. 1:59). Three years later, the victorious Judah Maccabbee selected the same date, 25 Kislev, as the time to rededicate the Temple, and inaugurated the restored worship of the One God at that time. (I Macc. 4:54) Judah and the assembly of Israel subsequently decreed an annual, eightday festival, to begin on 25 Kislev.
Thus, the answer to the question— Why does Hanukkah begin on 25 Kislev? Is it because that is the date originally chosen by Antiochus to defile the Temple, then chosen by Judah to undo the original damage? But we still need to understand why Antiochus chose 25 Kislev.
Antiochus sought to impose pagan worship upon the Jews. Specifically, which pagan deity? The best scholarly conjecture is Dionysius, the god of intoxication. The pig was the favorite sacrificial animal of the cult of Dionysius, which would explain why Antiochus forced the Jews to consume swine flesh. The month for the Greek veneration of Dionysius was Poseidon, which is the same as Kislev.
Now, why the 25th? Many scholars conjecture that Antiochus wanted to impose a winter solstice festival, and that may be—although Kislev 25 was not the solstice in 167 BCE. Alternately, it may be that Antiochus was forcing a particularly loathsome celebration of his birthday.
We read in another ancient account of Hanukkah, Second Maccabbees, that Antiochus forced Jews to partake of the meat of pagan sacrifices on his monthly birthday, i.e. on the day of the month that corresponded to the date of his birth. The likelihood is that he was born on the 25th; hence, while he erected the pagan altar in the Temple on the 15th of Kislev, he began the compulsory sacrifices on it on the 25th. (I Macc. 1: 54, 59)
It is well known that the Christian celebration of December 25 is an attempt to co-opt an existing pagan festival. Saturnalia was December 25, and by Christianizing it, the Church gave itself the spoonful of sugar to help its medicine go down.
Thus, it turns out that Christmas and Hanukkah are connected by the number 25, a time of month otherwise never used for Jewish holidays. Both are responses to paganism: the Christian Christmas an attempt to swallow the festival, and the Jewish Hanukkah, an attempt to undo the damage caused by the pagan tyrant who, like Pharaoh before him, celebrated his birthday by acts of cruelty.
—Rabbi Michael Panitz, Temple Israel