I want to thank everybody for their great answers!
In hindsight 150 words was far too few! My bad.
One common misconception many people had was that Mary had to have been immaculate in order for Jesus to be sinless. This isn’t true. If it were, it would mean that Mary’s Mother, Anne, would have had to be immaculately conceived also (and her mother, and her mother . . .). While It wasn’t necessary that Mary be sinless, it was fitting.
In this post I’d like to show how I would have answered the objection, my answer in no way is meant to be the answer (like the upside down answers at the back of a cross word book), but some of you asked for it.
I’ll then display the 1st, 2nd, and 3rd best answers.
No where in Sacred Scripture does it say that Mary was sinless. Rather, it says, “all have sinned and fall short of the glory of God” (Romans 3:23). The Immaculate conception is an invention of the Catholic Church which every Christian should reject as false!
There are three claims being made here: 1) Mary’s sinlessness isn’t taught in Sacred Scripture. 2) That Romans 3:23 is a good reason to think Mary was a sinner, and 3) the immaculate conception is something the Catholic Church invented.
Let’s address them in order:
1. This isn’t a good argument for at least two reasons.
First, not everything we are bound to believe as Christians is taught explicitly in Scripture. For example, The Bible doesn’t teach us what books belong in it (there is no inspired index).
Secondly, I can only think of only a couple of places (here and here) where the sinlessness of Christ is taught explicitly (there are certainly places which teach it implicitly, but then I would say the same of Mary). If this is true of Christ, why would we expect to find Mary’s sinlessness taught explicitly.
2. Romans 3:23 is not a universal claim. It admits at least one exception, Jesus Christ (not to mention babies and severely retarded persons). If Christ, the new Adam, is an exception, then Mary, the new Eve , could be an exception also.
3. Though the immaculate conception was not officially defined until 1854, that doesn’t prove that it’s an invention of the Catholic Church. The Divinity of Christ, for example, was not officially defined by the Church until the 4th century, the two natures of Christ (Divine and human) until the 5th, neither example proves that the Church “invented” these doctrines.
Rather, the immaculate conception, the Divinity of Christ, and the hypostatic union were believed since the apostolic age, yet in primitive form (St. Peter almost certainly woulnd’t have said of Christ, “Oh Jesus? Yeah, the dude is one person who subsists in two natures; Divine and human. Cool, no?”)
To show that Mary’s sinlessness was held by the earliest Christians, let me offer an excerpt from St. Augustine of Hippo, writing in the 400’s:
We make an exception for the Blessed Virgin Mary, whom, for the sake of the Lord’s honour, I would in no way like to be mentioned in connection with sin. Do we not know why she was granted a greater grace in view of the complete victory over sin, she who merited to conceive and give birth to him who obviously had no sin? (De natura et gratia, n. 42).
Learn more about what the earliest Christians believed and taught by getting Jimmy Akin’s awesome book, The Father’s Know Best.
I selected the winners based on accuracy, creativity, and sticking to the word count (something I totally didn’t do, but hey, it’s my site).
I have emailed the winners.
I hope that everyone will be a good sport about the answers I chose. It’s my hope that through exchanging ideas that we will grow together into more informed and effective apologists.
1st Prize (book and mp3)
Without the teaching authority of the Catholic Church, you have no basis for your belief that “something in the Bible has to be true,” including Romans 3:23. With no external verification, the Bible might just be a bunch of old books as truthful or fictitious as Homer’s epics or the legend of King Arthur. If you believe the Bible is Truth because it claims for itself that it is Truth, then wouldn’t you be obligated to believe this post? After all, it says it is true right at the beginning.
The Catholic Church was the first entity to consider St. Paul’s letter to the Romans to be the inspired Word of God. “The Bible is God’s Word” is itself, and necessarily so, an invention of the Catholic Church. If you believe that “invention,” why do you not believe our other “inventions?” – Sean Flynn
2nd Prize (mp3)
If Paul literally means ALL have sinned, and you admit no exceptions whatsoever, then you must include Jesus in your register of those who have sinned. If it seems unreasonable to you that Jesus has sinned, then perhaps there is more context in the rest of Paul’s writings. Let’s explore those together, shall we? – Luke
3rd Prize (mp3)
Many times in scripture the word “all” is used but there may be some exceptions- Similar to John baptizing all the nations (Matt. 3:5). Some exceptions to having sinned include Jesus, aborted babies, people with special needs, to name a few. Jesus (sinless) is the fulfillment of the Old Testment Adam. Mary is the fulfillment of the Old Testament Eve and also sinless as everything in the new perfects the old covenant. – Jordan
 Why is Mary the new Eve? Simply put, the first woman—herself a virgin—consented to the (fallen) angel and brought forth death upon the human race. The second women—herself a virgin—consented to the angel and brought forth life himself (and the possibility of eternal life) for the human race.