Jesus is coming back to earth. That is both good news and bad news. It's good news for those who know Him and embrace His teachings. It is bad news for those who don't. When He returns there will be a time both of tremendous blessing and of life ending judgment.
We know He is coming back because He promised that He would.
The second coming of our Messiah Jesus is mentioned in several different areas of scripture.
John 14:3 "And if I go and prepare a place for you, I will come again, and receive you to Myself; that where I am, there you may be also.
Revelation 19:11-20 gives a vivid description of the second coming of Jesus.
This is a great question with a two part answer. The second coming of Jesus needs to be viewed with two events or phases in mind. The first is The Rapture. The second is His physical return to earth.
When the bible teaches that no man knows when Jesus will come, (Matthew 24:36) it is referring to Jesus coming for His church in the rapture event. Since Jesus doesn't physically touch the earth at this time (believers are caught up in the air to be with him) it doesn't qualify as His return to earth but does qualify for His return for His bride, the church.
The second event or phase associated with Jesus second coming is His physical return to earth sometimes referred to as the "glorious appearing." We don't know exactly when that will be right now but we do know that Jesus comes at the end of the Tribulation Period. Since the Tribulation period is seven years long and Jesus comes at the end, once the tribulation period (also known as the time of Jacob's trouble) begins those left behind after the rapture will be on a seven year countdown.
Remember that Jesus first coming lasted around 32 years (His birth until His crucifixion). His second coming will last at least 7 years when viewed as coming in phases starting with the rapture, followed by tribulation, ending with His physical return to earth.
And in that day His feet will stand on the Mount of Olives, which is in front of Jerusalem on the east; and the Mount of Olives will be split in its middle from east to west by a very large valley, so that half of the mountain will move toward the north and the other half toward the south. (Zechariah 14:1-4)
At this time the Millennial Kingdom will begin.
The Zohar, the basic book of Kabbalah system, speaks of an earthquake which will occur when a rising star appears to the world.(1) Also see note under miscellaneous section.
2 Thessalonians 2:1-9 Concerning the coming of our Lord Jesus Christ and our being gathered to him, we ask you, brothers, not to become easily unsettled or alarmed by some prophecy, report or letter supposed to have come from us, saying that the day of the Lord has already come. Don't let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness is revealed, the man doomed to destruction. He will oppose and will exalt himself over everything that is called God or is worshiped, so that he sets himself up in God's temple, proclaiming himself to be God. Don't you remember that when I was with you I used to tell you these things? And now you know what is holding him back, so that he may be revealed at the proper time. For the secret power of lawlessness is already at work; but the one who now holds it back will continue to do so till he is taken out of the way. And then the lawless one will be revealed, whom the Lord Jesus will overthrow with the breath of his mouth and destroy by the splendor of his coming. The coming of the lawless one will be in accordance with the work of Satan displayed in all kinds of counterfeit miracles, signs and wonders...
Immediately after the distress of those days 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. At that time the sign of the Son of Man will appear in the sky, and all the nations of the earth will mourn. They will see the Son of Man coming on the clouds of the sky, with power and great glory. And he will send his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of the heavens to the other.(Matthew 24:29-31)
The purpose of His (Jesus) first coming was to suffer for the sins of the world, die on the cross, and rise again-without which there would be no eternal life. We who live in the church age (present age) have the benefit of being able to look back and determine which prophecies have already been fulfilled by His first coming and which have yet to be fulfilled by His second coming.(2)
There are still messianic prophecies that are unfulfilled. While Jesus did fulfill some prophecies when he was here the first time, he will fulfill the rest when he comes the second time. For more information on Jesus and prophecy visit to the Prophecy area of Jewishroots.net.
Zechariah teaches us about the Second Coming Of King Messiah (Zechariah 14:1-4). For a more in depth look into Zechariah 14:1-4 please read The Day Of The Lord.
Some theological circles inside Judaism look for two different Messiahs to come instead of the same messiah coming two different times. Other Jewish schools of thought viewed one messianic coming that would fulfill all the prophecies at once. Because things like world peace and Israel being delivered from Roman oppression didn't occur with His first coming many Jews found this reason enough to reject Him as Messiah. For more on the belief of two Messiah's please read Two Messiahs In Judaism.
There was one generation that was alive when Jesus came the first time almost 2000 years ago and there will be one generation alive when He returns.
After Jesus returns and things are in order (some say an additional 75 days) it will be time for the Millennial Kingdom to begin.
There is a very old theory relating to Messiah's arrival that predates the birth of Jesus. There was a Jewish tradition that the Messiah would come to fulfill His kingdom promises in the seventh millennium from creation. This was derived from combining the seven days of creation and the biblical statement that, with God, "one day is as a thousand years" (2 Peter 3:8 and Psalm 90:4). Since He created the earth in six days and then rested, and since, "One day is as a thousand years," the 4000 years of the Old Testament history that had already passed suggested that Messiah would come (back) in 2000 years. That would be followed by the Millennial Kingdom which would correspond to the seventh day of creation.
Note: JewishRoots.Net does not recognize the Zohar as being 100 percent divinely inspired and information about its reference is only included for informational purposes.
1). Soncino Zohar, Shemoth, Section 2 Page 8a.
2). The Popular Encyclopedia of Bible Prophecy by Tim Lahaye.