Praised be Jesus and Mary, now and forever.
In the first reading, St. John tells us, "Children, it is the last hour," he says, 1 John 2:18. That phrase, "last hour," refers to the final phase of salvation history, which was set in motion by Jesus Christ. 
In his writings, St. Paul refers to this last epoch as "the end of the ages." He says that in 1 Corinthians 10:11. St. Peter, in his first epistle, calls it "the end of the times" (1 Peter 1:20). The Old Testament was essentially a time of preparation for the coming of Christ. Then, in what St. Paul calls "the fullness of time," God sent His Son, born of a woman, born under the law. We read that in Galatians 4:4. 
Now, after the Resurrection and Ascension of Christ into Heaven and after Pentecost, after the outpouring of the Holy Spirit, we are in the final phase of history. We've been in this phase now for almost 2,000 years. To us, of course, that seems like a long time, but we have to remember: for the Lord, St. Peter tells us, "A single day is like 1,000 years, and 1,000 years are like a single day, he says. (2 Peter 3:8). So, time is as nothing in God's eyes. We know time is always on His side, and we also know God's timing is always perfect. 
Regarding time, another truth that we need to keep in mind is what David tells us in Psalm 144:4, where he says, "Man is like a breath; his days are like a passing shadow." Our life really is like a breath of air—it’s here today, gone tomorrow. The Prophet Isaiah puts it even more eloquently in Isaiah 40:6-8 he says this: "A voice says, ‘Call out.’ Then I said, ‘What shall I call out?’ All flesh is grass, and its loveliness is like the flower of the field. The grass withers, the flower fades, when the breath of the Lord blows upon it. The grass withers, the flower fades, but the word of our God stands forever." In other words, everything passes very quickly. Everything passes away except for God and except for His word.
It's good to be reminded of these truths on the last day of the year. Saint John, in his first reading, also warns the faithful by saying, "Just as you heard that the Antichrist was coming, so now many Antichrists have appeared. Thus, we know this is the last hour" (1 John 2:18). Here in his letter, "Antichrist" refers to anyone who denies that Jesus is the Messiah. The word comes from the Greek “antichristos”, which means "against Christ." That title refers to anyone who separates Christ's humanity from His divinity, or anyone who embraces heresy. 
Here it would be good to distinguish between formal heresy and material heresy, but for the purposes of brevity, we won’t delve into that this morning. 
Antichrists are those who seduce people away from the truth to a false messianism, and who bring about a persecution of the faithful. The Antichrist who will come at the end of time will offer humanity a solution to all its problems, but only at the price of apostasy—of rejecting Christ and the Church—and also through the glorification of humanity itself. This is essentially what Monsignor Robert Hugh Benson wrote about in his book “The Lord of the World”. 
As the Apostle said, "Just as you heard that the Antichrist was coming, so now many Antichrists have appeared" (1 John 2:18, again). So let's be careful not to fall into the trap of the Antichrists—the trap of denying Christ in our words or in our actions, or denying our faith in our words or in our actions, or turning our backs on the Church or on the teachings of the Church when it becomes seemingly convenient for us to do so.
So overall, I think these are two important messages or thoughts on which to end the year with: first, that our life is no more than a breath, and secondly, we should be aware of anyone or anything which may want to seduce us or take away from us that which is most important in life—namely, our faith in Christ and in His Church. Far more important than anything else is to live and to die in God's grace. Jesus says in Mark 8:36, "What shall it profit a man if he gain the whole world but lose his own soul or forfeit his own life?"
The fact that our life is no more than a breath, though, as the psalmist says, shouldn’t be a cause for worry or anxiety, or sadness. Instead, we should take to heart the words of our Seraphic Father, St. Francis, when in his exhortation, he tells his friars, he says to them, he says, O most beloved friars and sons, forever blessed, hear me, hear the voice of your father. Great things we have promised; greater have been promised us. Let us observe the former; let us aspire to the latter. Pleasure is short; punishment everlasting. Suffering is slight; glory infinite. Many are called; few are chosen. Retribution to all. Brethren, while we have time, let us do good." 
So let’s begin the new year with those words in mind: "While we have time, let us do good.” That's from Galatians 6:10.
Whatever we do in this upcoming year, let it be something that we can offer to the Lord.
We'll just close here by giving St. Thérèse of Lisieux the last word. In her letters, she writes: "We only have the fleeting moments of our life in which to love Jesus." In another letter, she says: "There is only one thing to do during the night—this, the unique night of life, which will only occur once—that is to love, and above all, to love Jesus." 
In this nighttime of life, in this night of faith, this walk of faith that we have in this life, what’s the only thing that’s really worth doing? Loving, and especially loving our Lord. 
So let’s close this new year by asking Our Lady for the grace of a strong faith and for the grace of perseverance, no matter what the new year might bring. 
Praised be Jesus and Mary, now and forever.