No one knows when Jesus will return to Earth, but he instructed his disciples to be on the look out and expect him to arrive at any moment. It says in Matthew 24:36-39, “But concerning that day and hour no one knows, not even the angels in heaven, nor the Son, but the Father only. For as the days of Noah, so will be the coming of the Son of Man. For as in those days before the flood they were eating and drinking, marrying and giving in marriage, until the day when Noah entered the ark, and they were unaware until the flood came and swept them all away, so will be the coming of the Son of Man (ESV).
Mark’s gospel emphasized the importance of vigilance in waiting for Christ’s return. He said, “Be on guard, keep awake. For you do not know when the time will come. It is like a man going on a journey, when he leaves home and puts his servants in charge, each with his work, and commands the doorkeeper to stay awake. Therefore stay awake – for you do not know when the master of the house will come, in the evening, or at midnight, or when the rooster crows, or in the morning – lest he come suddenly and find you asleep. And what I say to you I say to all: Stay awake” (Mark 13:32-37, ESV). Jesus’ command to stay awake was probably meant as a reference to the spiritual complacency that many Christians fall into when they realize Christ might not return during their lifetime. Although it’s been 2000 years since Jesus left, it’s very unlikely it will take another 2000 years for him to return.
Jesus used the parable of the fig tree to encourage his followers to watch for the signs of his second coming. He said, “Now learn a parable of the fig tree; When his branch is yet tender, and putteth forth leaves, ye know that summer is nigh: so likewise ye, when ye shall see all these things, now that it is near, even at the doors” (Matthew 24:32-33). One of the clearest signs that Christ’s return is near is that the Nation of Israel has been reestablished and God’s people are once again living in the Promised Land.