Catholics around the world — who are already observing the first week of the Advent season — mark the Solemnity of the Immaculate Conception on Thursday, Dec. 8, a day that signifies the conception of the Blessed Virgin Mary in the womb of her mother, St. Anne.
"The Catholic Church’s teaching on the Immaculate Conception is, in my opinion, one of our most beautiful yet frequently misunderstood doctrines," Fr. Cassidy Stinson, a priest of the Diocese of Richmond, Virginia, told Fox News Digital.
"In brief, this feast day celebrates the belief that Mary, the mother of Jesus Christ, was prepared for her unique and special role as the Mother of God by the gift of being redeemed and protected at the time of her conception from the effects of original sin, which we normally inherit from our parents," he also said.
While many people assume the phrase "immaculate conception" refers to the conception of Jesus, this is incorrect, said Stinson.
"Often, this doctrine is easily confused with an event that’s probably more familiar to us: the conception of Jesus by the power of the Holy Spirit in the Annunciation," he said.
The Annunciation is celebrated nine months before Christmas on March 25.
And while the Solemnity of the Immaculate Conception is "centered on Mary," Stinson clarified that "like everything that the Catholic Church celebrates about our lady, at its heart it always leads us back to Jesus, her son."
"Christians believe that Jesus is fully God and fully human, and that He received His bodily flesh from Mary," Francis Vu, content lead at the Christian prayer app Hallow, told Fox News Digital.
"It follows that He would take on humanity from someone who was without sin."
In the United States and in a handful of other countries, the Solemnity of the Immaculate Conception is a holy day of obligation.
Catholics must attend Mass on that date or a vigil Mass the evening before, says the website for the United States Conference of Catholic Bishops.
In parts of Europe, as well as in many countries in Central and South America, the Solemnity of the Immaculate Conception is also a public holiday.
The Marian title of "Immaculate Conception" is particularly important for American Catholics.
In 1846, the bishops of the United States unanimously declared the Blessed Virgin Mary, under her title of the Immaculate Conception, as the patroness of the United States, according to the website of the Basilica of the National Shrine of the Immaculate Conception.
The Basilica of the National Shrine of the Immaculate Conception is located in Washington, D.C., near the campus of the Catholic University of America.
It is the largest Catholic church in North America; the shrine is known as "America's Catholic Church."
The U.S. bishops’ declaration came eight years before the Vatican officially defined the dogma of the Immaculate Conception, Vu told Fox News Digital.
In 1854, Pope Pius IX issued an apostolic constitution called "Ineffabilis Deus," which defined that Mary was immaculately conceived without sin.
This, however, was not the first time that Mary’s immaculate conception was taught, noted Vu.
"Christians had been honoring Mary under the title of the Immaculate Conception for centuries prior," he said. "There are records as early as the 7th and 8th centuries showing this widely held belief in the Church."
The timing of the solemnity, which is during the liturgical season of Advent, is a reminder to Christians "that God also desires a deep friendship with us" — and, like with Mary, "He wants to make us holy and reside intimately with us," said Vu.
"He gives us the grace to be able to say ‘yes’ to Him, as Mary did, and receive Him into our hearts," he added.
The Immaculate Conception, as well as any other Marian celebration, "does not overshadow God," said Vu, as it "points to the power of God's redemption and its effects on mankind."
Said Vu, "Mary is for all Christians, not just Catholic Christians, and this relationship does not take away from our singular devotion due to God."