We Catholic old-timers have probably heard many more "sermons" on Mary than "homilies."

A sermon is a talk on some religious subject. A homily is a talk based entirely on biblical theology. The sermon-giver picks a pious topic and expounds. The homilist, using a passage from Scripture, helps his audience better understand God working their lives.

While there are no limits on the subject matter and direction of sermons, homilies must be routed along the tried-and-true theological path trod by God's followers for almost 3,000 years. The bishops at Vatican II urged Eucharistic preachers to return to the early Christian practice of homilizing and halt the modern custom of sermonizing.

What God doesBY definition, a homilist must know and be comfortable with biblical theology. Along with the history and direction of our sacred writings, he is to pass on the many nuances the authors have built into their works. Such a preacher, for instance, will point out how the author of Sunday's first reading (2 Sam 7:1-5, 8-11, 16) slips so effortlessly from David's intention to build a "house" for Yahweh to Yahweh's longing to build a house for David: a clear example of the ancient faith insight that we're not on earth to do things for God, but to reflect and build on what God is doing for us.

A homilist will also note Paul's fascination in the second reading with God's revelation of "the mystery hidden for many ages" (Rom 16:25-27). In the midst of believing he knows everything about God and God's plan, this good Pharisee discovers a completely unexpected person and message. The disclosure forces him to examine more carefully both his sacred writings and those persons (the Gentiles) whom popular religion had consigned to an inferior position in God's design. The Apostle always believed that his narrow field of vision stopped him from appreciating all that God was accomplishing for God's people.

Finally, in the Gospel (Lk 1:26-38), a homilist will recall Luke's definition of a good Christian and notice how that definition applies to Mary.

Writing just 50 years after Jesus' death and resurrection, Luke confronted a familiar problem. Some in his community were starting to think that faith was simply a matter of mind and heart. They listened to the Word Jesus proclaimed, felt good about it, then walked away believing they were good Christians -- never making any attempt to integrate His message into their daily lives.

Luke, knowing that faith involved not only listening to the Word but also carrying it out, used Mary as the vehicle to convey his message. She's the one person in his Gospel who puts God's Word into action after she hears it. Remember what Luke has Jesus say about His mother in 8:21, and how He responds to the woman who yells at Him from the crowd in 11:28? In each case, the key to faith revolves around listening and doing.

Let it be done

That's why the Annunciation plays such an important role in Luke's Gospel. After Gabriel speaks of Mary's favored status with God, proclaims the good news of her divine motherhood, and clears up any doubts by giving her a sign that he's on the up and up, Mary finally speaks the words so dear to Luke's heart: "Let it be done to me as you say."

She agrees to carry out the Word Gabriel has addressed to her. She doesn't just walk away from this event, pleased that she's heard words which no other human has ever heard. Without her willingness to "do," we would have no salvation.

Luke's theology at this point is simple. Those who find out what God wants and, like Mary, do it, are Jesus' true followers. Those who just hear the Word but never put it into action are deceiving themselves into believing they have faith. Christian faith is a matter of continually making Jesus' faith a part of our lives. Day in, day out, we must listen, then do. If, when we go to bed tonight, we can't think of one thing we did different today because of our faith, we've probably been faithless people.

Any good homilist would remind us of that infidelity.