As I'm sure you're aware, tomorrow is predicted to be the end of the world. Again. But is it really? In 2 Peter 3:10, it says "But the day of the Lord will come like a thief, and then the heavens will pass away with a roar, and the heavenly bodies will be burned up and dissolved, and the earth and the works that are done on it will be exposed." Do you really think that a thief would put it on a calendar that they would break into your house? Probably not. He would be a pretty lousy thief. So even if He did come tomorrow, we wouldn't know!
Also, the reason that some think that the world will end tomorrow, is that a Mayan calendar ran out of room on 12/21/12. So, I mean, they had to stop somewhere, but that doesn't mean that it's the end of the world. Also, wasn't the end predicted to end last year as well? And several other times before that? We can see clearly that we have absolutely no idea when the end will happen, no matter how many predictions are made. It could happen within the next 200 seconds, or the next 200 years. God didn't tell us because He doesn't want us to just live however we want until the end of the world, and turn around at the last minute. He wants us to dedicate our whole lives to worshiping Him.
But what if the world were to end? What if God had told us that the world would end tomorrow? How would our lives be different? Well, for starters, most people probably wouldn't care about buying things, or having money, because it'll all be gone in a day anyway! It would be much easier to be generous and kind, because we would want to make sure that we make it into heaven, and everything would be gone anyway, so why not?! This is how God wants us to live. He didn't tell us when because He wants us to live like the world is about to end all the time. He wants our lives to be dedicated to Him, so we can be prepared for the end, whether it's tomorrow, or in 100 years, we should always live like the end is near, because that is how God commanded us to live, always doing our best to serve Him. Thank you for reading. :)