This can best be answered by looking at a document called 'Justification by Faith' written in 1983 by the Lutheran-Roman Catholic Dialogue Group in the United States:

"Our entire hope of justification and salvation rests on Christ Jesus and on the gospel whereby the Good News of God's merciful action in Christ is made known; we do not place our ultimate trust in anything other than God's promise and saving work in Christ."

Also in this document the following is said:

"Catholics can speak of justification by faith or even of justification by faith alone insofar as they teach, as do Lutherans, that nothing prior to the free gift of faith merits justification and that all of God's saving gifts come through Christ alone. Catholics stress, however, that the indwelling Holy Spirit brings about in believers not only assent and trust, but also a loving commitment that issues in good works."

Indeed, the Bible does make mention of the need for 'good works':

Matthew 25:31-46, of which I will now excerpt:

"Then the King will say to those on His right, 'Come, you who are blessed by My Father; take your inheritance, the kingdom prepared for you since the creation of the world. For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me... whatever you did for one of the least of these brothers of mine, you did for me."

In the Letter of James we also see the following:

'... faith, by itself, if it has no works, is dead.' (James 2:17)

'... I by my works will show you my faith.' (James 2:18)

Which only makes sense, since if we do live a spiritual and faithful life, we WILL go out out of our way to help those in need. Hence, the two really do go hand in hand, and as Catholics, one is not placed above the other because they work in unison.

IMHO, as long as there is a drastic difference in the most basic concept of every religous belief, salvation, then there will be no unity.

I'd like to think that we do not differ as much as people might think.

As a matter of fact, on October 31st in Augsburg Germany, the Lutheran World Federation and the Catholic Church drew up a document called 'The Joint Declaration' , of which the 'first basic truth' is the following:

First, justification is a free gift bestowed by the Trinitarian God and centers on the person of Christ, who became incarnate, died and rose. In being related to the person of Christ through the work of the Holy Spirit, we enter into a condition of righetousness. This is not something we merit, but is freely bestowed. And so 'together we confess: By grace alone, in faith in Christ's saving work, and not because of any merit on our part, we are accepted by God and receive the Holy Spirit, who renews our hearts while equipping and calling us to good works.'

This pretty much restates that which we covered in an earlier part of this discussion. But it does bring to the forefront a very important and special document.. Lutherans and Catholics have been able to come to an agreement on one of the most hotly debated topics that exist between the two, and because of this Declaration, I'd like to think we are closer to religious unity (or at least acceptance) than we all might think.