Advent calls to mind the centuries of expectation for the Messiah, but also focuses on the expectant Blessed Virgin Mary.

In its observance of the days leading up to Christmas, the Church implicitly recognizes that an unborn child is a human being, a person with the same dignity as anyone who has already been born. Christ once was an embryo, a fetus, an unborn child. He who died on the cross to save mankind is the same person who was conceived in the womb of the Blessed Virgin Mary.

As Christ is in our midst from the moment of the Annunciation, a woman who is pregnant for the first time is already a mother.

As if to drive that message home, Pope Benedict XVI has asked all the bishops of the world to join him as he celebrates a “Vigil for all nascent human life” on Nov. 27, the evening before the First Sunday of Advent.

It’s the first of its kind, and the symbolism could hardly be more meaningful, the need hardly more significant.

Pope Benedict will lead the main celebration in St. Peter’s Basilica. The vigil will include Eucharistic adoration to “thank the Lord for his total self-giving to the world and for his incarnation which gave every human life its real worth and dignity.” That’s according to a letter from Cardinal Antonio Cañizares Llovera, prefect of the Congregation for Divine Worship and the Discipline of the Sacraments, and Cardinal Ennio Antonelli, president of the Pontifical Council for the Family.

Say the cardinals: “We are all aware of the dangers that today threaten human life, as these are promoted by relativistic and utilitarian culture which disables human sensitivity and often renders it powerless to acknowledge the inherent and equal dignity that human life possesses, regardless of its stage or condition. We are therefore called to be more than ever ‘the people of life’ (John Paul II, Evangelium Vitae, 79) both with our prayer and in our commitments. At this extraordinary vigil, celebrated by the Supreme Pastor of the Church and all particular churches, we shall thus be invoking the Lord to bestow his grace and light for the conversion of hearts and, at the same time, we shall be offering to the entire world an outstanding ecclesial witness of the Church’s culture of life and love.”

In an accompanying set of guidelines for celebration of the vigil, an outline for a possible homily notes that the mystery Christians celebrate at Christmas is “God’s full approval, his great Yes, to human life.”

The vigil will be celebrated worldwide, and, of course, each culture will receive it in its own way. In America, it comes just after Thanksgiving Day, during a month when Election Day fades into memory and commerce-driven expectations for “the holidays” rise sharply.

This year’s midterm elections gave Catholic Americans some reasons to be grateful. The House of Representatives has more pro-life members than ever, and that gives us some reasons for hope. We can hope not only that votes on life issues go somewhat better, but also that a growing pro-life caucus in Congress gives the pro-life movement more credibility in Washington.

But we know from experience that it’s unwise to put one’s hope totally in politics and politicians. Candidates who ran on messages of change, promising to not be like career politicians, often end up being … career politicians. Freshman congressmen with ideals of doing what’s best for America and not being beholden to special interests often run up against the reality of having to compromise principles.

And so, it is not simply through politics that we’ll win the battle for life. The vigil for nascent life reminds us that it is through conversion, as the cardinals noted in their letter.

The vigil is a challenge to us, particularly American Catholics, to observe Advent differently this year. Instead of letting ourselves be caught up in the consumerist spirit of holiday shopping, we can try, rather, to give of ourselves in whatever situations present themselves — in imitation of him who gave himself in the Incarnation and on the cross.

Someone needs five minutes of your time, and you are scurrying to get a project done? Sacrifice the five minutes, and you give that person a gift that has no price.

Know of someone who will be alone on Christmas — even someone whose company is less than desirable? Set a place for him or her at your table.

Looking forward to sleeping in on a free Saturday morning? Find out if there’s a pro-life group that stands outside an abortion business praying the Rosary and offering help to desperate mothers who feel their only choice is to “terminate.” Or search out a soup kitchen that needs a hand.

Notice that a friend or relative is veering from the truth? Let your love for that person guide your prayerful guidance of his conscience.

As the materials for local celebrations of the Pope’s vigil suggest, “the celebration of the gospel of life ought to be carried out in one’s own daily life through a spirit of charity towards everyone, by our own self-giving (Evangelium Vitae, 87-91). Core to this task is the promotion of a culture of life, where ‘the people of life,’ with their vast and diverse associations and institutions, are called to fulfill a unique and irreplaceable service for life within society.”

It’s most appropriate, then, that the Pope will include in the vigil this prayer written by his predecessor, John Paul II (at the end of Evangelium Vitae). Let us make the prayer our own as we enter this season of great expectancy:

O Mary, bright dawn of the new world, Mother of the living, to you do we entrust the cause of life: Look down, O Mother, upon the vast numbers of babies not allowed to be born, of the poor whose lives are made difficult, of men and women who are victims of brutal violence, of the elderly and the sick killed by indifference or out of misguided mercy. Grant that all who believe in your Son may proclaim the Gospel of life with honesty and love to the people of our time. Obtain for them the grace to accept that Gospel as a gift ever new, the joy of celebrating it with gratitude throughout their lives and the courage to bear witness to it resolutely, in order to build, together with all people of good will, the civilization of truth and love, to the praise and glory of God, the Creator and lover of life.