Christmas is one week from today. You'll probably have one of three reactions to that news: panic ("I haven't finished my shopping yet!"), relief ("It's almost over!"), or genuine joy ("It's the most wonderful time of the year!"). Different people fall into different categories, but it's difficult to remain truly neutral about Christmas Day.
Most of us, I believe and would hope, fall more into the joy response (admittedly after a month or so of panic). We recognize this is a day, a season, to celebrate. Here is something special. Granted, we mark it in not-exactly-biblical ways -- I'm sure even the Wise Men would cringe at the mockery we've made of their gift-giving -- but we still see joy and love as the hallmarks of this time of year. People are generally more cheerful, more generous, more kind at Christmas. The world just seems a happier place. As the Muppets phrased it, "It is the summer of the soul in December."
Of course, the Christ Child wasn't born to make us happy; he was born to save our souls. And yet that salvation itself is an inexhaustible source of unmitigated joy. First Peter 1:8-9 puts it this way: "Though you have not seen him, you love him; and even though you do not see him now, you believe in him and are filled with an inexpressible and glorious joy, for you are receiving the end result of your faith, the salvation of your souls." This isn't a fleeting, earthly happiness; this is joy unspeakable, a heart so ecstatic that words fail.
Such joy comes, as Peter says, from the salvation offered to us through the sacrifice of Jesus, whose birth we celebrate one week from today. Do you have this joy? You can.