The Solemnity of the Immaculate Conception is often the subject of confusion. Some people seem to think that the “conception” referred to is Jesus. But the Church celebrates the conception of Jesus March 25, the Solemnity of the Annunciation, because Jesus — “true God and true man” — lived in Mary’s womb, like any human child, for nine months.

For much of Christian history, March 25 also marked the start of the civil year (instead of Jan. 1).

Yet Dec. 8 marks not Jesus’ conception but Mary’s. As the novena prayer puts it, “O, Mary, conceived without sin, pray for us who have recourse to thee.” When, during the Marian apparitions at Lourdes, Bernadette asked Mary her name, Our Lady replied simply: “I am the Immaculate Conception.”

Pope Pius IX proclaimed the dogma of the Immaculate Conception in 1854 and, despite the Pope’s clear teaching, some Catholic theologians have tried to diminish its significance, claiming it to be an impediment to ecumenical dialogue with Protestants. They’re wrong.

While the theology of Mary (Mariology) was one time prone to accentuate the Blessed Mother’s special privileges, Catholic theology since Vatican II has tended rather to focus on Mary as the model disciple, the model Christian.

Mary is, after all, purely human. St. John Paul II liked to quote the Second Vatican Council, which taught that “Jesus Christ fully reveals man to himself,” but we can build on that perspective. Mary also reveals true humanity; Mary is, after all, what human beings should have been like, but for sin.

Sin is not part of the natural human endowment. Sin (and its punishment, death) should not have been part of human destiny.

Mary, conceived without sin by God’s prevenient grace, assumed to God body and soul, “when her earthly life was ended,” shows us what humanity could have been but for sin. But she also shows us what we can be, in a fallen world, by cooperating with God’s grace.

The Venerable Tomas Morales (1908-1994), a Spanish Jesuit and founder of the male and female secular movements the Crusaders of Mary, is a candidate for canonization. His spirituality puts great focus on the Immaculate Conception, and Crusader communities attach great attention to the vigil of the Immaculate Conception.

In his meditations on the Immaculate Conception, Father Morales captures the essence of understanding the Blessed Virgin Mary as model disciple and model Christian in this saying: “I am God’s, only God’s, all God’s and always God’s” (Soy de Dios, solo de Dios, toda de Dios, siempre de Dios). We might take that saying as a motto for life.

I am God’s: Mary was God’s most perfect example of love outside the Trinity.

As Father Morales points out elsewhere, sanctity is first and foremost God’s work: The sheer variety of saints points to the diversity of God’s love, the many ways in which it finds expression.

Jeremiah (1:5) captured the idea of the Immaculate Conception when, examining his own vocation, he speaks in God’s voice: “Before you were formed, I knew you; before you were born, I set you apart.”

From all eternity, amid all the people who ever have or ever will walk this earth, all of whom God infinitely loves, he loved in a special way a young girl in a small Jewish town over two millennia ago and chose her in a special way to bring the rest of that humanity back to God, to God who would also be her Son.

And just as every other human being who must respond to his or her vocation individually and freely, Mary had to say “Yes” — and did — because “I am God’s.”

And only God’s: The First Commandment is not primarily about prohibiting the worship of idols with the heads of hawks or exaggerated genitalia. The First Commandment is about putting first things first — and nothing else in that place. Mary was “only God’s.”

As Father Morales points out, Mary depended wholly on God. As we approach Christmas, consider that dependence. Her vocation as Theotokos, as Mother of God, was simply impossible by human standards. She broaches that topic: “How can this be, since I do not know man?” And God — who takes those he loves seriously — tells her that his power will overshadow her. She no longer asks how, no longer wants details. “Let it be done as you say.”

“Let it be done,” even though she has no idea how she will explain this to her fiancé, or how — based on his reaction — she might be exposed to death, or how she would cope if he “put her away.” She is “only God’s,” and she leaves her trust in him. And all God’s is her commitment: Body and soul, she belongs to God.

The Church affirms that exclusivity in honoring her as the Blessed Virgin Mary. A society that increasingly does not recognize sexual intercourse as a sign of a deeper belonging is unlikely also to understand the value of virginity. Nor is it likely to recognize the depth and truth of that love.

That is why, perhaps more than anything, the Solemnity of the Immaculate Conception, honoring the patroness of the United States, should this year be a day of renewal of the Church in this country, recovering the purity of love and sexual purity that can begin to repair the squalor of this year’s clerical homosexual sex-abuse scandals.

Mary may be the pattern of pure holiness never violated; but Mary Magdalene is also the pattern that holiness can be recovered.

And always God’s: Mary’s fiat was absolute, irrevocable and indissoluble. She was accompanied: by Joseph to Bethlehem, by John to Calvary; but — in both cases — she was accompanied to follow her vocation, not flee it.

Mary teaches us that love has its own logic, a logic that chooses and persists in that course — now God’s and always God’s.

And that is why the Solemnity of the Immaculate Conception leads us to the Solemnity of the Assumption, because she who was God’s, only his, totally his and always his, is now his — forever — body and soul, in heaven.

Let’s make the words of Father Morales — “I am God’s; only his, all his and always his” — our own this Marian feast day.

John M. Grondelski writes from Falls Church, Virginia.