"He was conceived by the Holy Spirit, and born of the Virgin Mary"
Coming to the article of the Creed dealing with faith in Jesus, we begin to see a more in-depth description. It's because this is the core of our faith. Who and what Jesus is has been the topic of discussion from the inception of the Church. Early on there were those who taught things that departed from the historic faith. Normally their teachings centered on certain aspects of Christ. They typically denied His full deity, or His full humanity. The Church in its wisdom, and guided by the Holy Spirit who was given to lead them into all truth, established the firm teaching that we find contained in the Creed.
"He was conceived by the Holy Spirit". Our Lord's entrance into our world did not come through the normal channels. He had no earthly father. Rather the Holy Spirit came upon the Virgin Mary and conceived our Lord within her womb. This was not sexual. It was supernatural. It was completely other.
It had to be this way. From the fall into sin in the Garden, man has been tainted with sin. As the psalmist says, "In sin was I conceived." For our Lord to remain pure from this taint of sin, He could not have a human father.
But this also means that His mother could not pass on sin to Him either. Surely, we know that He took His humanity, that is, His flesh, from the Virgin Mary. The Church stresses that Mary was always a Virgin. She is designated by that title. It is because in her conception, she became a holy vessel. As the Ark of the Covenant of the Old Testament contained the Word of God, so Mary also contained the Word of God. She could not be "touched" by a husband after this event. As surely as God struck down Uzzah for touching the Ark, He would have likely done the same to anyone who touched the Ark containing His only beloved Son.
In order to preserve our Lord from the taint of sin received from Mary, the Church teaches that her own conception was immaculate, that is to say, without sin. By a special grace of God in lieu of the work that Christ was to accomplish, Mary was saved from the taint of original sin. This is how it is that she refers to God as her Savior. She was saved by His grace from ever experiencing sin, rather than, as it is for all the rest of us, being rescued from the midst of sin.
So how is it that our Lord is truly human when He had these special circumstances preserving Him from sin? Well, believe it or not, sin is not native to being human. Remember that God created the first humans immaculate- without sin. Yet, they fell to temptation and chose sin. So it was with our Lord and our Lady. As the new Adam and Eve, they still could have chosen sin, but they did not. Their victory over sin has become the means of our own. That is, that all who believe in Jesus are baptized and enter into His own death and resurrection. In Him, we are made what people once were, and were created to be- holy. Our Lord's opportunity to do this for us was made possible by Mary's steadfast faithfulness throughout her life and in giving her consent to be the vessel to bring Christ into the world.
What does this mean for us? It means that we do not need to be subject to sin any longer. We can come to Jesus to be healed and restored. We can be delivered from sin. We can return to our original holiness for which we were created. We can do this through our Lord Jesus Christ. He who came to earth under such extraordinary circumstances has made it possible for us all to be made like Him and to live with Him forever.