Today is the Feast of the Immaculate Conception in the Catholic Church. Catholics believe that Mary, the Mother of God, was conceived without original sin. She is, therefore, immaculate- spotless. Now for non-Catholics this appears to be troublesome, even blasphemous. In fact, the whole idea of Marian devotion is hard to grasp.
To understand all this one must understand two fundamental concepts of the Catholic Church. First, whatever we believe about Mary flows from what we believe about Christ. We do Christology first, then Mariology follows. So we believe Jesus is fully God. Therefore Mary must be the Mother of God. We believe that being God, the Son of God could not dwell in a temple that was tainted by sin. Therefore Mary must be immaculate. Finally, having sanctified the womb of Mary, it could not possibly be returned to common uses and so we believe she is Ever-Virgin.
Secondly, Catholics believe in the Church. That is, we believe that the Church is of divine origin and that it cannot be conquered by error or sin. Therefore, when the Church makes a definitive statement of faith and morals, we simply accept it. We trust the Church is being directed by the Holy Spirit and so she cannot err. We do not have to figure it all out for ourselves. We simply receive it by faith.
Putting these two emphases together, we find a number of things that the Church teaches about Mary that we receive and practice by faith. The Immaculate Conception is one such thing. Marian devotion is another. Now, to distinguish between the two, the Immaculate Conception is a dogma. It must be believed by all the faithful. However, Marian devotion, while based on dogma, is very much in the realm of discipline, or that which may be practiced in various ways by the faithful. So there are some differences.
Why is Mary so important to the Catholic Church? Well, she is the mother of our Lord. Isn't that enough? But in additon, it was her "yes" to God that opened the way for Christ to come. So she plays a very pivotal role in God's plan of salvation. Also, being the mother of our Lord, she becomes the mother of all who believe in Him- who are His brothers and sisters. As our mother, she sets an example for us to follow, and intercedes on our behalf so that we will gain eternal life.
On this day, we not only honor Mary, but we glorify God in Mary. We rejoice in the manifold wisdom of God in His marvelous work. We are in awe of Mary because we are in awe of God. As we rightly honor Mary, we bring glory to God who chose her as His precious instrument to bring salvation to the world.