If it is going to be such a huge event, why does the Jesus say that we should be watching, lest we miss the event?
When a thief breaks into the house at night, he comes in and goes out quietly, such that nobody even notices him... It is only in the morning that the homeowner realizes that he has been there because of the telltale signs he left behind.
Rev 3:2-3 Be watchful, and strengthen the things which remain, that are ready to die: for I have not found thy works perfect before God. Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.
Rev 16:15 Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame.
Luke 12:39-40 And this know, that if the goodman of the house had known what hour the thief would come, he would have watched, and not have suffered his house to be broken through. Be ye therefore ready also: for the Son of man cometh at an hour when ye think not.
Matthew 24:42-44 (KJV) Watch therefore: for ye know not what hour your Lord doth come. But know this, that if the goodman of the house had known in what watch the thief would come, he would have watched, and would not have suffered his house to be broken up. Therefore be ye also ready: for in such an hour as ye think not the Son of man cometh.
Matthew 24:42-44 (TLB)So be prepared, for you don’t know what day your Lord is coming. Just as a man can prevent trouble from thieves by keeping watch for them, so you can avoid trouble by always being ready for my unannounced return.
2 Peter 3:10-13 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up. Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness, Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat? Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.
Mark 13:32-37 But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father. Take ye heed, watch and pray: for ye know not when the time is. For the Son of Man is as a man taking a far journey, who left his house, and gave authority to his servants, and to every man his work, and commanded the porter to watch. Watch ye therefore: for ye know not when the master of the house cometh, at even, or at midnight, or at the cockcrowing, or in the morning: Lest coming suddenly he find you sleeping. And what I say unto you I say unto all, Watch.