Christmas Day—December 25—which celebrates the birth of Jesus Christ， the founder of the Christian religion， is the biggest and best-loved holiday in the United States.
According to the Bible， the holy① book of Christians， God decided to allow his only son， Jesus Christ， to be born to a human mother and live on earth so that people could understand God better and learn to love God and each other more. “Christmas” —meaning “celebration of Christ”—honors the time when Jesus was born to a young Jewish woman Mary.
Mary was engaged② to be married to Joseph， a carpenter， but before they came together， she was found to be with child. Because Joseph， her husband， was a righteous man and did not want to expose her to public disgrace③， he had in mind to divorce her quietly. But after he had considered this， an angel of the Lord appeared to him in a dream and said， “Do not be afraid to take Mary home as your wife， because what is conceived④ in her is from the Holy Spirit. She will give birth to a son， and you are to give him the name Jesus， because he will save his people from their sins.”
Although the exact date of the birth of Jesus nearly 2，000 years ago is not known， the calendar on the supposed⑤ date divides all time into B.C. (Before Christ )and A.D. ( a Latin phrase， Anno Domini， “in the year of our Lord.”)For the first 300 years， Jesus’ birthday was celebrated on different dates. Finally， in the year 354， church leaders chose December 25 as his birthday.
① holyadj. 神圣的，圣洁的
② engagev. 使订婚
③ disgracev. 使丢脸，使蒙受耻辱
④ conceivev. 怀（胎），抱有（想法、感情）
⑤ supposedadj. 假定的，想象的
圣诞节的起源
12月25日的圣诞节是庆祝基督教创始人耶稣基督为了纪念耶稣的诞生的日子，是美国最大、人们最喜欢的节日。
据基督教徒的圣书《圣经》说，上帝决定让他的独生子耶稣基督投生人间，找个母亲，然后就在人间生活，以便人们能更好地了解上帝、学习热爱上帝和更好地相互热爱。“圣诞节”的意思是“庆祝基督”，庆祝一个年轻的犹太妇女玛丽娅生下耶稣的时刻。
玛丽娅已和木匠约瑟夫订婚。可是，在他们同居之前，约瑟夫发现玛丽娅已怀孕。因为约瑟夫是个正派的人，又不想把这件事说出去让她丢脸，所以他想悄悄地和她分手。他正在考虑这事时，上帝的天使出现在他的梦中，对他说，“不要嘀咕了，把玛丽娅娶回家。她怀的孩子来自圣灵。她将生下个男孩子，你们给孩子起名叫耶稣，因为他将从罪恶中拯救人们。”
尽管耶稣的确切生日并不清楚，大约是在2，000年前，但是日历按着假定日期把时间分为公元前（耶稣基督诞生前）和公元后（A. D. 是拉丁文缩写，意思是“有了我们主——耶稣的年代”）。在公元后的头300年间，耶稣的生日是在不同的日子庆祝的。最后，在公元354年，教堂的领导人把12月25日定为耶稣基督的生日。
