Advent is a season observed in many Western Christian churches, a time of expectant waiting and preparation for the celebration of the Nativity (birth) of Jesus at Christmas. At least in the Roman Catholic, Anglican, Lutheran and Methodist calendars, Advent starts on the fourth Sunday before December 25, the Sunday from November 27 to December 3 inclusive. Christians believe that the season of Advent serves a reminder both of the original waiting that was done by the Hebrews for the birth of their Messiah as well as the waiting of Christians for Christ's return. The theme of readings and teachings during Advent is often to prepare for the Second Coming while commemorating the First Coming of Christ at Christmas. With the view of directing the thoughts of Christians to the first coming of Jesus Christ as savior and to his second coming as judge, special readings are prescribed for each of the four Sundays in Advent. The usual liturgical colour in Western Christianity for Advent is purple or blue.
The O Antiphons are Magnificat antiphons (devotional compositions sung responsively as part of a liturgy) used at Vespers of the last seven days of Advent in various liturgical Christian traditions.
Each antiphon is a name of Christ, one of his attributes mentioned in Scripture. They form the basis for each verse of the popular Advent hymn, "O come, O come, Emmanuel". They are:
December 17: O Sapientia (O Wisdom)
O Wisdom, coming forth from the mouth of the Most High,reaching from one end to the other mightily,and sweetly ordering all things: Come and teach us the way of prudence.
Isaiah had prophesied: "The spirit of the Lord shall rest on him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and the fear of the Lord. His delight shall be in the fear of the Lord." Isaiah 11:2-3
"[...] he is wonderful in counsel, and excellent in wisdom." Isaiah 28:29
December 18: O Adonai (O Adonai)
O Adonai, and leader of the House of Israel,who appeared to Moses in the fire of the burning bush and gave him the law on Sinai: Come and redeem us with an outstretched arm.
Isaiah had prophesied: "[...] but with righteousness he shall judge the poor, and decide with equity for the meek of the earth; he shall strike the earth with the rod of his mouth, and with the breath of his lips he shall kill the wicked. Righteousness shall be the belt around his waist, and faithfulness the belt around his loins." Isaiah 11:4-5
"For the Lord is our judge, the Lord is our ruler, the Lord is our king; he will save us." Isaiah 33:22
December 19: O Radix Jesse (O Root of Jesse)
O Root of Jesse, standing as a sign among the peoples; before you kings will shut their mouths, to you the nations will make their prayer:
Come and deliver us, and delay no longer.
Isaiah had prophesied: "A shoot shall come out from the stock of Jesse, and a branch shall grow out of his roots." Isaiah 11:1
"On that day the root of Jesse shall stand as a signal to the peoples; the nations shall inquire of him, and his dwelling shall be glorious." Isaiah 11:10
December 20: O Clavis David (O Key of David)
O Key of David and sceptre of the House of Israel; you open and no one can shut; you shut and no one can open: Come and lead the prisoners from the prison house, those who dwell in darkness and the shadow of death.
Isaiah had prophesied: "I will place on his shoulder the key of the house of David; he shall open, and no one shall shut; he shall shut, and no one shall open." Isaiah 22:22
"His authority shall grow continually, and there shall be endless peace for the throne of David and his kingdom. He will establish and uphold it with justice and with righteousness from this time onwards and for evermore." Isaiah 9:7
"...To open the blind eyes, to bring out the prisoners from the prison, and them that sit in darkness out of the prison house."Isaiah 42:7.
December 21: O Oriens (O Dayspring)
O Morning Star, splendour of light eternal and sun of righteousness: Come and enlighten those who dwell in darkness and the shadow of death.
Isaiah had prophesied: "The people who walked in darkness have seen a great light; those who lived in a land of deep darkness—on them light has shined." Isaiah 9:2
December 22: O Rex Gentium (O King of the nations)
O King of the nations, and their desire, the cornerstone making both one:
Come and save the human race, which you fashioned from clay.
Isaiah had prophesied: "For a child has been born for us, a son given us; authority rests upon his shoulders; and he is named Wonderful Counsellor, Mighty God, Everlasting Father, Prince of Peace." Isaiah 9:6
"He shall judge between the nations, and shall arbitrate for many peoples; they shall beat their swords into ploughshares, and their spears into pruning-hooks; nation shall not lift up sword against nation, neither shall they learn war anymore." Isaiah 2:4
December 23: O Emmanuel (O Emmanuel)
O Emmanuel, our king and our lawgiver, the hope of the nations and their Saviour: Come and save us, O Lord our God.
Isaiah had prophesied: "Therefore the Lord himself will give you a sign. Look, the young woman is with child and shall bear a son, and shall name him Immanuel." Isaiah 7:14
An Advent calendar is a special calendar which is used to count down or celebrate the days of Advent in anticipation of the birth of Christ which we celebrate at Christmas on December 25th. It also symbolizes our anticipation of the Second Coming of Jesus Christ. It was traditionally counting down the 24 days to Christmas Eve but many today do count down 25 days to Christmas Day. Modern Advent Calendars usually have a way of concealing small treats or gifts.
An Advent Calendar would be a great way to teach your children about the birth of Jesus Christ, the anticipation of Jesus. If it becomes just another way to give your children candy then you've missed the opportunity to use it as a teaching tool. In fact, the original Advent Calendars were just ways to mark the season. The Advent used to be a time of fasting and penitence. You would make a mark on your front door with chalk or cross it off a calendar. Paper calendars for the season would have a little door which, when opened, just showed the number of the day, no treats involved. Jesus was the "treat".
Most American children have enough candy or small gifts, it's not like they need any more. So the whole purpose of an Advent Calendar is to anticipate Christ (not the secular Xmas). Tell the Christmas story to your children and talk about what a gift God gave us when he sent His Son, Jesus Christ, to this world to die for our sins and give us forgiveness, salvation and eternal life. Then let them open up the bag/drawer/door and let them have a tiny gift. I was impressed with the Advent Calendars that had a creche (nativity scene) and each drawer opened contained a figure in the scene and the child could add the figure to the creche.