In the beginning, God created the heavens and the earth. (Genesis 1:1) And everything that has a beginning…also has an ending. Just as God brought about the beginning, so God will bring about the ending. We’ve come to the end of the Christian calendar; the last Sunday in the church year. Next week is Advent; a new beginning. But today we consider the Last Day as described by the only one who knows: Jesus Christ. It’s the end of the world as we know it.
If we’re honest, we will admit that it’s impossible for us to imagine everything in the universe coming to an abrupt, sudden end, isn’t it? We tend to think in terms of a slow wasting away, a steady and predictable winding down. In fact, that’s how we like it. We like to know when our cars, our furnaces, our bodies are going to die – because then we think we have some control, some time to prepare, perhaps something we can do to prevent it. Human pride doesn’t want to think about a last day, a day when everything we know simply stops, ends, vanishes in a flash – completely outside of our control. But that is precisely how Jesus describes the end: the sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the heavenly bodies will be shaken. It doesn’t seem possible; but it is certain, just as certain as the fact that God created everything from nothing in the beginning.
How does it feel to know that at any moment everything you’ve ever known could be destroyed? The tendency is to doubt it, dread it, or dismiss it. Either we doubt all this end times talk and think “yeah, I’ll be dead and gone long before then” – or we dread the coming end and live in fear, searching for signs, hoping to somehow wrap our arms around it and bring it under our control. The world simply dismisses it as religious speculation; fake news. So the world just goes on, eating and drinking, marrying and giving in marriage (Matthew 24:38) – oblivious to the fact that one day, it’s all going to come crashing down. But just as Jesus promises that this universe will be shaken, so he shakes up our tendencies. He doesn’t want us to wait for the End of the world with doubt, dread, or dismissal; but rather to trust his Word, be watchful and hopeful.
There’s only one reason the end of the world is good news: At that time men will see the Son of Man coming in clouds with great power and glory. Jesus’ return will be a dramatic reversal of his Ascension into heaven. (Acts 1:1-11) Instead of a cloud hiding him from sight, the clouds will reveal his arrival. Instead of 11 disciples gazing at the sky, the whole world will witness his return. Instead of veiling his divinity under the cloak of humiliation, Jesus will return with great power and glory. But despite the differences, one thing won’t change. The one who returns in judgment will be the same one who was born in a manger, who sought out the sick and the sinner, who brought forgiveness and healing, who suffered, was crucified, died and rose again to pay for our sins. This same Jesus (Acts 1:11) that the disciples had seen and heard and touched – that we have heard and touched and received in Word and Sacrament – will be the one returning in the clouds.
He will send his angels and gather his elect from the four winds, from the ends of the earth to the ends of the heavens. It will be the grand family reunion that the children of God have been waiting for, a day when the Church – that appears so hopelessly scattered and fragmented today – will be visibly and permanently united as one. The contrast is striking: even as everything in this universe is falling apart, the church is put back together.
While it will be a day of judgment and destruction for those who rejected him, Jesus doesn’t mention that here. His goal is to fortify the faith and hope of his disciples. For believers, the end of the world isn’t a day of death but a day of life. Just as he called the appearance of false prophets and wars and disasters birth pains (Mark 13:8), so he compares these cosmic signs to a fig tree budding on the cusp of summer. In the midst of terror and destruction, Jesus is bringing life! The destruction of the world as we know isn’t the end for us, it is the beginning – the beginning of life in a new heaven and new earth – just as God intended it! Who would have guessed it? Who could have known it? It’s the exact opposite of what scientists and physicists claim will happen when the sun goes dark. Which is why the only one we can trust to inform us about the end of time is the one who came from heaven. (John 3:13)
I tell you the truth, this generation will certainly not pass away until all these things have happened. Heaven and earth will pass away, but my words will never pass away. There are those who claim that the Bible has been revised over the centuries to remove inaccuracies and contradictions. If that were true, I would ask, how did this verse survive? It would seem that it would have been wise for the early Church to just scrub this verse, because it appears that Jesus made a big mistake: the world didn’t end in his generation, nor has it ended 50 generations later.  But this verse still stands there in black and white – and it forces us to think more deeply about what Jesus means. 
In the most important sense – these things did happen. The sun was darkened, the earth shook, the dead rose, the laws of nature bent before their Maker, when Jesus died on the cross. That was, in a very real sense, the end of the world as we know it. Jesus shouldered the entire curse of sin that permeates this world – all the guilt, shame, pain, sorrow, decay – and carried it to the cross where the fury of God’s wrath destroyed it and him. That was the true Judgment Day for believers – because God made him who had no sin to be sin for us, so that in him we might become the righteousness of God. (2 Corinthians 5:21) And when we were baptized, this world died to us and we died to this world. (Galatians 6:14)
But these things (the signs of the end) also happened (began happening) forty years later – when the Roman army overran Jerusalem and tore down the temple until not one stone was left upon another. At the time believers viewed this as the beginning of the end – they expected Jesus to return at any moment. In fact, in every generation of believers have lived as though the world would end any day. Paul did. (1 Corinthians 7:29) The early church fathers did. Luther did. Because they saw the signs all around them and believed Jesus’ words. And even though their lives ended before the world did, they weren’t wrong.
Because living today as if it will all end tomorrow – that’s what it means to be Christian. Which is why Satan works so hard to confuse and distort the Biblical message of the end times. He uses his same old lie: did God really say? (Genesis 3:1) with great effect. He leads us to focus all our effort and attention – not on God’s Word, but on the things and opportunities of this world. He even leads us to believe that mankind has some role in either bringing about or delaying the end of the world. Don’t fall for his lies. Heaven and earth will pass away, Jesus swears. Everything you see, taste, touch, smell – everything you bought on Black Friday – it will all be destroyed. But the words of the Lord will never pass away – will never have to be revised or corrected. When? When will the end come? When do I need to start getting serious about this Christianity stuff? No one knows but the Father.
So don’t worry about when, that’s above our pay-grade, that’s God’s business. Instead, Jesus says, today: be on guard! Be alert! Jesus says we are to be like watchmen waiting for the owner to return. He could come at any time of day or night – and whenever he does, he expects us to be ready, focused, awake. That doesn’t mean that you don’t go to sleep at night. It doesn’t mean you go and sell all your possessions. It doesn’t mean you don’t plan for the future. It doesn’t mean that you quit your job and stand around looking at the skies waiting for Jesus to appear. (The angels told the disciples not to do that! Acts 1:11) It means that you go about the work God has given you to do – whatever it is – with the understanding that he could return at any moment, and he wants to find you doing his will.
It should be obvious (but, sadly, it’s not) it means that there is never any good, appropriate time to go wandering away from the Lord’s presence and power in Word and Sacrament. The idea that there are some times in life – the decade after you’re confirmed, when work or family demand your Sunday mornings, when the spirit is willing but the body is weak (Matthew 26:41), when it’s inconvenient – that God understands that sometimes some things are more important than worshipping him. That is a damned lie. Jesus never said that. This is what Jesus says: What I say to you, I say to everyone: ‘Watch!’
Jude lays out a simple preparedness plan: build yourselves up in your most holy faith. (Jude 20-21) Build yourself up in your faith, the faith you were baptized and confirmed into, the faith that was once for all entrusted to the saints (Jude 3), faith that confesses Jesus as your personal Savior and Lord who redeemed you and made you his own by shedding his own blood. Repent, daily. Study the Christian faith. Learn the Christian faith. Know what you believe and why you believe it – don’t put it off, and don’t think that it’s just for kids, because one day, it will be too late.
Keep yourselves in God’s love as you wait for the mercy of our Lord Jesus Christ to bring you to eternal life. This is amazing: the world as we know it will be destroyed, but Jesus will come bringing mercy, not wrath. Mercy is kindness to those who don’t deserve it. Mercy is what God gives us here and now when he announces that we have been justified in his sight – declared “not-guilty”, that our names have been written in the book of life in Baptism, that in Communion we receive a foretaste, a down-payment of what’s to come. To keep in God’s love means nothing more and nothing less than to take every opportunity to receive God’s forgiving love in Christ. That’s why we worship, every week, all year long. Here is where God distributes the grace and the guidance we need to be ready and watchful and prepared for the day he brings this world to a screeching halt. It’s not about doing something for God, it’s about receiving a preview of eternity, sampling the Lamb’s wedding feast, it’s about gathering with fellow believers, encouraging each other to remain watchful as the day approaches. (Hebrews 10:25)
If any of it depended on us, we’d be doomed. If it depended on our vigilance, our faith and our godly living – we wouldn’t survive the end of the world. But, thank God, he doesn’t leave it up to us – he placed that burden on Jesus. The blood Jesus shed on the cross will not only shield us from the destruction that is coming, but is also the garment of righteousness that we will wear to the grand reunion of believers in glory. One day this world as we know it will end. And that’s good news, because then we will experience life in the world Jesus is preparing for us, life free from sin and sorrow, from pain and death. That is a day worth preparing for. Amen.
 Assuming that 40 years = a generation
 Another possible interpretation is that generation refers to all who reject Jesus as God and Lord – thus, unbelief won’t pass away until all these things happen. See also Matthew 16:4.