“Watch out that you are not deceived. For many will come in my name, claiming . . . ‘The time is near.’ Do not follow them”—Luke 21:8 NIV

“Don’t believe them”—Luke 21:8 NLT

“Refuse to join them”—Luke 21:8 NJB

Jesus spoke about his “return” (Luke 19:12 NIV) in the Bible. Jesus knew that the exact time of “when he returns” (Matthew 24:46; Luke 12:43 NIV) would be an issue for Christians through the ages. For the last 2,000 years many predictions have been made about when Jesus would return. But they have all proven false. For example:

“We ask you, brothers, with regard to the coming of our Lord Jesus Christ not be shaken out of your minds suddenly, or to be alarmed either by a ‘spirit,’ or by an oral statement, or by a letter allegedly from us to the effect that the day of the Lord is at hand”—2 Thessalonians 2:1,2 NAB

 According to the Bible, no one can accurately predict the time when the end of this world will occur. Therefore, we should avoid any individuals or groups who claim to do so!

“At that time if anyone says to you, ‘Look, here is the Messiah!’ or, ‘There he is!’ do not believe it. For false messiahs and false prophets will appear and perform great signs and wonders to deceive, if possible, even the elect. See, I have told you ahead of time. So if anyone tells you, ‘There he is, out in the wilderness,’ do not go out; or, ‘Here he is, in the inner rooms,’ do not believe it.” (Matthew 24:23-26)
“At that time if anyone says to you, ‘Look, here is the Messiah!’ or, ‘Look, there he is!’ do not believe it. For false messiahs and false prophets will appear and perform signs and wonders to deceive, if possible, even the elect. So be on your guard; I have told you everything ahead of time.” (Mark 13:21-23)
“There will be signs in the sun, moon and stars. On the earth, nations will be in anguish and perplexity at the roaring and tossing of the sea. People will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken. At that time they will see the Son of Man coming in a cloud with power and great glory. When these things begin to take place, stand up and lift up your heads, because your redemption is drawing near.” (Luke 21:25-28 NIV)
The end will be sudden, unexpected by all, including Jesus’ disciples. When the end finally does come, then everyone on earth will know it, either in a saving way, or in a destructive way.

“Now, brothers and sisters, about times and dates we do not need to write to you, for you know very well that the day of the Lord will come like a thief in the night. While people are saying, ‘Peace and safety,’ destruction will come on them suddenly, as labor pains on a pregnant woman, and they will not escape.” (1 Thessalonians 5:1-3)
Just like a thief in the night, then end will catch people off-guard.

Jesus, speaking to his closest disciples, said,  “That day will come on you unexpectedly, like a trap. For it will come on all those who live on the face of the whole earth” (Luke 21:34b, 35a NIV).

“Therefore keep watch, because you do not know on what day your Lord will come.  But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. So you also must be ready, because the Son of Man will come at an hour when you do not expect him.” (Matthew 24:42-44)
Christians are told to be ready at all times, because Jesus is coming when you don’t expect him.

“At midnight the cry rang out: ‘Here’s the bridegroom! Come out to meet him!’” (Matthew 25:6)
The “midnight” return of Jesus is spoken of here, which represents him coming when he is least expected.

“Therefore keep watch, because you do not know the day or the hour.” (Matthew 25:13)
You don’t know the time. In fact, no one does! 

“But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father.” (Matthew 24:36)
“But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father.” (Mark 13:32)
Even Jesus said he doesn’t know the day or hour. This implies that it is impossible for anyone to figure out the time when Jesus will return. The end of the world will be sudden and unexpected.

“Be on guard! Be alert! You do not know when that time will come. It’s like a man going away: He leaves his house and puts his servants in charge, each with their assigned task, and tells the one at the door to keep watch. Therefore keep watch because you do not know when the owner of the house will come back—whether in the evening, or at midnight, or when the rooster crows, or at dawn. If he comes suddenly, do not let him find you sleeping. What I say to you, I say to everyone: ‘Watch!’” (Mark 13:33-37)
Be alert, because you don’t know the time. Be like the doorkeeper, always ready and alert to your Master’s coming.

“Look, I come like a thief! Blessed is the one who stays awake and remains clothed, so as not to go naked and be shamefully exposed.” (Revelation 16:15)
Jesus is coming as a thief, unannounced, sudden and unexpected. If the time of his coming could be accurately predicted, there would not be so many warnings in the Bible that it could not be predicted! 

The point is repeatedly emphasized in the New Testament to be ready for Jesus’ return at all times, but don’t try to figure when that time will be. The Bible says the end of the world will be sudden and unexpected.