Your priest may be wearing a subdued shade of rose today, instead of the Advent purple/violet. And this is because the introit of the Mass is
Gaudéte in Dómino semper: íterum dico, gaudéte, Dóminus enim prope est.
which is to say, Rejoice in the Lord always, and against I say, Rejoice, for the Lord is near. Also, S. Paul says to us at the head of the second reading, Rejoice always. Rejoicing in the Lord is part of the Christian attitude to life, no matter what life throws at us. Such was the attitude of the Hebrew people, of whom Christ permitted himself to be a part. In the midst of great trials, of the great misfortune that came with being a relatively small people, living in a land that was and still is the desire of all the nations. We inherit that joy, in all circumstances, as Paul says.
And so we are at the mid-point of Advent, and the great feast is almost upon us. The Lord is near. There is a sense of us being almost-there. Despite the market-place telling us repeatedly that it's Christmas time, we are still only almost-there. Time and memory are a strange experience in the sense that the Christian tradition presents them to us [link]. When we mark calendar events such as anniversaries as Catholics, the event has both already happened and is still going on. So, at Holy Mass, we are gathered around at the foot of the Cross and around the Empty Tomb on Easter morning. So, also, at this time, we live in Judaea before the birth of Christ, feeling the electricity in the air as the arrival of the God-man becomes imminent, although we cannot see where he may be coming from.
And that brings us almost naturally to S. John the Baptist. John was the last of the prophets of the time before Christ, and he was very like his predecessors in his sense of excitement at the vision he saw of a Light beginning to dawn. The time was fulfilled, he knew, and the words of S. Isaiah in today's first reading could very well be his: The Spirit of the Lord is upon me, for He has anointed me to bring good news to the poor, to heal the broken-hearted, to proclaim liberty, to announce the favour of God, and so I rejoice with all my heart. It is the voice of Christ, of course, speaking centuries ago in Isaiah, now again in John, and a but a moment later in His own person. Time melts together in that joyful announcement of the advent of God, expected and yet unexpected. Expected in itself, unexpected in its manifestation. We are all of us to be like S. John the Baptist, for we are now heralds of the Second Coming of Christ, His coming in Majesty. We must be together, as a Church, a voice crying in the wilderness, Make a straight way for the Lord, for His return is imminent. S. Paul tells us how, in brief, in the second reading: always rejoice, pray endlessly, give thanks, keep what is good, avoid evil.