I know that Jesus Christ will come again when everybody has heard the gospel. Right? Well, a lot of people at school say that the world is going to end in 2012. Why are they saying this?
"But of that day and hour no one knows, not even the angels of heaven, but My Father only" (Matthew 24:36).
Isn't it interesting that so many people claim to know more than Jesus? Jesus stated that only the Father knows when the world will end. I would have to conclude that anyone who makes a prediction concerning precisely when the end of the world will come is a liar.
Jack Van Impe is the false prophet who is one source of the 2012 date. As Wikipedia states:
"Televangelist Jack Van Impe has, over the years, predicted many specific years and dates for the second coming of Jesus, but has continued to move his prediction later. Many of these dates have already passed, and he recently pointed to 2012 as a possible date for the second coming. Van Impe no longer claims to know the exact date of the Second Coming, but quotes verses which imply that mankind should know when the second coming is near."
Since a true prophet only speaks God's word and God is never wrong, this very statement is sufficient evidence that Jack Van Impe is a false prophet. "And if you say in your heart, 'How shall we know the word which the LORD has not spoken?' - when a prophet speaks in the name of the LORD, if the thing does not happen or come to pass, that is the thing which the LORD has not spoken; the prophet has spoken it presumptuously; you shall not be afraid of him" (Deuteronomy 18:21-22).
Another popular source is the claim that the world will end on December 21, 2012, because the ancient Mayan calendars go that far. This date is popular among groups known as "New Agers."
People have made numerous predictions regarding the end of the world -- all of them have been wrong. See "220 Dates for the End of the World! Date Setters!" for a partial list.
Returning to your question, what you are referring to regarding Jesus' return is:
"And this gospel of the kingdom will be preached in all the world as a witness to all the nations, and then the end will come" (Matthew 24:14).
There is one problem that many people overlook: which end? It is easy to jump to the conclusion that Jesus is talking about the end of the world, but other things have also come to an end. If you read the context of the quote, Jesus is discussing the end of Jerusalem. I have a detailed article on this topic, so instead of repeating it here, please take a look at "Understanding Matthew 24."
What Jesus predict did come true. Before the end of Jerusalem, the gospel was preached to all the world. "Because of the hope which is laid up for you in heaven, of which you heard before in the word of the truth of the gospel, which has come to you, as it has also in all the world, and is bringing forth fruit, as it is also among you since the day you heard and knew the grace of God in truth" (Colossians 1:5-6).
The Bible does state what will come immediately before the end of the world:
"Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power. For He must reign till He has put all enemies under His feet. The last enemy that will be destroyed is death" (I Corinthians 15:24-26).
So the end will come after Jesus conquers death, which is logical because at the end is when all the dead arise for judgment.