Advent comes from the Latin adventus, which means a coming, and translates the Greek word parousia, which designates not the coming of Jesus at his birth but his coming again to judge the world on the Last Day. Advent has in fact three comings, or turnings toward, to prepare for, which culminate in the liturgy for Christmas, Christ's Mass, which uniquely in the church year has three distinct liturgies. There is the mass in the night to celebrate the historical coming or birth of Jesus, the mass at dawn to celebrate the coming or birth of Jesus in the heart of believers as evidenced in the shepherds who went to the manger, and the mass during the day which celebrates the eternal generation of the Son in the Trinity in the being of God in which redeemed Man will fully participate after the end of time, which has been the subject of the final Sindays of the church year before Advent.
Advent then precedes Christmas similar to Lent preceding Easter, a time of repentance and preparation. For both seasons, church vestments etc are purple, the colour associated both with penance, our part, and royalty, his part as King of kings. However, the purple is a little different than the Lent purple, darker, the royal purple rather than the Roman purple, as the seasons, while similar, are distinct in that to which they lead. And in the rite of Salisbury, called Sarum in Latin, England, which had a hybrid liturgy of English and French influences following the Norman Conquest in 1066 (William of Normandy appointing its bishop, St Osmund, how's that for apostolic succession!) the Scripture readings and other prayers proper to the day were different than the Roman rite, as was the colour of vestments, which was blue. This use of blue as the colour for Advent has had a more general usage in the West in recent years, though with the Roman propers (or the new Roman ones from its three year cycle from the 1960s, which will not be considered here -- one can look them up and put on a little Simon and Garfunkle or other holdovers of the time if one is so inclined). It is not the first time the Sarum rite has influenced Western usage, generally through its appropriation into the Church of England. The traditional Lutheran practice of counting Sundays in the rest of the church year from Trinity Sunday rather than Pentecost is a Sarum influence too. For that matter, the liturgical colour for Advent in the Eastern churches is generally red! And in the West, from the fourth or fifth century or so Advent was a 40 day time of fasting and penance much like Lent, starting on 11 November, the feast of St Martin of Tours, Martin Luther's namesake (and see my post on 11 November and this feast, "What's An Armistice"), with the day being something like Mardi Gras, Fat Tuesday, in Lent. This "quadragesima sancti Martini", the forty days of St Martin, died out by the late Middle Ages, and Advent as it is generally known in the West took shape and is what we use to-day.
Each Sunday emphasises a different aspect of the preparation and the comings noted above. Following are the Scripture passages used for the Introits and Scripture readings. Roman usage (which they ditched at Vatican II) has the same Introits but varies as noted from ours in the Epistles and Gospels for the Western Advent. I had never understood this variation and mentioned that in the combox on One Lutheran ... Ablog! (see Blogroll on the sidebar). Pastor Benjamin Mayes responded citing Reed, The Lutheran Liturgy, p.438, which states our usage follows the Comes attributed to St Jerome and its final version, The Lectionary of Charlemagne, which Rome later modified to accomodate its new feasts. Comes is a Latin word meaning companion, here a companion book of readings for mass to the rite's service book itself and more commonly called to-day a Lectionary, from the Latin for "readings"; the list of the readings is still often called by its Greek name, pericope, meaning section, here the sections of Scripture appointed to be read. Psalm numbers as given below are the old Roman usage which followed the Septuagint, in which in terms of the Hebrew Bible Psalm numbering generally used now counts Psalms 9 and 10 as one psalm, likewise 114 and 115, and divides both 116 and 147 in two, so between 10 to 148 the numbering is different by one.
The First Sunday of Advent. (Ad te levavi)
Introit Psalms 24:1-3 psalm verse 24:4, Epistle Romans 13:11-15, Gospel Matthew 21:1-9.
Roman usage Gospel Luke 21:25-33 our second Sunday Gospel.
The Second Sunday of Advent. (Populus Sion)
Introit Isaiah 30:30 psalm verse 79:2, Epistle Romans 15:4-13, Gospel Luke 21:25-36.
Roman usage Gospel Matthew 11:2-10, our third Sunday Gospel.
The Third Sunday of Advent. (Gaudete)
Introit Philippians 4:4-6 psalm verse 84:2, Epistle First Corinthians 4:1-5, Gospel Matthew 11:2-10.
Roman usage Epistle Philippians 4:4-7 Gospel John 1:19-28, our fourth Sunday readings.
The Fourth Sunday of Advent. (Rorate coeli)
Introit Isaiah 45:8 psalm verse 18:2, Epistle Philippians 4:4-7, Gospel John 1:19-28.
Roman usage Epistle First Corinthians 4:1-5 Gospel Luke 3:1-6, our third Sunday Epistle, the Luke passage not used by us.
Some final notes. In some places, the traditional main dish for Christmas is goose. In fact, one of my favourite phrases in English, not suitable for reproduction here, derives from this custom, let the reader understand. The Christmas goose may derive from Advent when it was St Martin's Fast. Martin didn't really want to be a bishop, and is said to have hid himself in a flock of geese from those seeking him to persuade him to accept the post, whose noise nonetheless gave his location away. So goose became the main food for St Martin's Day kicking off Advent.
In Latin and Hebrew, the title of a text is usually the first word or two of the text rather than something separate. Accordingly, some of the Sundays of the church year are called from the first word of the first proper text to them, the Introit. This practice has fallen into disuse with many churches following Rome's 1960s revisionism of the lectionary. Or one can as my former synod did abolish Introits altogether! The third Sunday in Advent is known as Gaudete Sunday, from the opening of the Introit from Philippians Rejoice (gaudete, in Latin) in the Lord always and the coming joy of Christmas breaks into the time of preparation. Accordingly, purple is set aside this Sunday, and rose coloured vestments are used and the rose candle in the Advent wreath lit. Rose vestments are used only one other time in the church year, the Fourth Sunday of Lent, called Laetare from its Introit Rejoice (laetare, in Latin) Jerusalem, from Isaiah 66:10, in which the coming Easter joy similarly breaks into the season of preparation. Roman usage repeats the Gaudete passage as Epistle (or used to), whereas our usage will extend this on through Advent using the passage as the Epistle for the next and last Sunday of Advent.
Christmas is a warm time filled with comfort, family, presents, good food, along with our religious sentiments, for many of us. Christmas as in the event we celebrate was nothing like that. It was rough. Joseph wasn't the glowing saint of paintings and icons, he was a working guy with a pregnant wife about to give birth -- I've been there twice and that ain't easy under any circumstances, and my observation would be it ain't easy being the about to deliver wife either -- in town to follow the law and get counted in the census with all the hotels full and no place to put his family up but a stable for animals, and after the baby was born they had to put him in a feeding trough for animals. That's what away in a manger was. A manger is a feeding trough for animals, the word coming into English from the French to eat, in turn from the Latin to chew (mandere). Fact is, our word "munch" has the same root.
So the King of kings is put in a feeding trough for animals in a cold stable. You don't make up this kind of stuff. Humans who are gods in myth are emporers and such, not working class kids born in a barn. Top it all off, this child away in a feeding trough will one day give himself to be the food of eternal life, giving his body and blood for us to eat and drink as the pledge and promise of our salvation through the merits of his death and resurrection at mass. Guess it kind of fits then.
And you know what, for those whose Christmas isn't going to be all warm and cozy and filled with cheer, guess what, you're right in there with those at the first Christmas. That was a little rough too. Born in a stable, a feeding trough for a crib, and pretty soon his family having to high tail it out of town into political exile too. So you're not excluded at all, and can take it right to him, because he knows all about when Christmas isn't so merry. And he also knows all about how merry doesn't really get determined by what happens in this life, on Christmas or any other day!
To Thee have I lifted up my soul, in Thee, O my God, I put my trust. Let me not be ashamed, neither let my enemies laugh at me, for none of those that wait on Thee shall be confounded.
Psalm 24 (or 25, remember?):1-3 as used in the Introit for the First Sunday in Advent.