The end of the Seventieth Week corresponds to the time when the events of the great tribulation are "shortened":
"For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened" (Mt. 24:21-22).
The Lord Jesus will return to Jerusalem and deliver His people at the time of their greatest peril. Then after restoring Jerusalem then there will be signs in the heavens:
"Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken" (Mt. 24:29).
The prophet Joel describes what will happen after the signs in the sky:
"The sun and the moon shall be darkened, and the stars shall withdraw their shining. The LORD also shall roar out of Zion, and utter his voice from Jerusalem; and the heavens and the earth shall shake" (Joel 3:15-16).
This corresponds to the following verse:
"And then the sign of the Son of Man will appear in the sky, and then all the tribes of the earth will mourn, and they will see the SON OF MAN COMING ON THE CLOUDS OF THE SKY with power and great glory" (Mt. 24:30; NASB).
The coming of the Lord Jesus on the clouds of the sky will not occur immediately after the signs are seen in the sky. The Greek word translated "then" at Matthew 24:30 is tote, and one of its meanings is "of things future; then (at length) when things under discussion takes place" (Thayer's Greek English Lexicon).
After the signs in the sky the Lord Jesus says, "Watch, therefore; for ye know not what hour your Lord doth come" (Mt. 24:42).
His coming will not happen immediately after the signs in the sky. And the Lord's words that follow (Mt. 24:43-51) are a warning against apostasy because of the delay which even then shall still mark His coming:
"But and if that evil servant shall say in his heart, My lord delayeth his coming...The lord of that servant shall come in a day when he looketh not for him, and in an hour that he is not aware of" (Mt.24:48,50).
The only thing certain about the timing of His coming when He will be seen in the sky is that it will happen within the lifetime of the generation who sees the signs in the sky.
When He does come there will be a world wide judgment that is compared to the great flood of Noah's day:
"But as the days of Noah were, so shall also the coming of the Son of man be. For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark, And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be. Then shall two be in the field; the one shall be taken, and the other left. Two women shall be grinding at the mill; the one shall be taken, and the other left" (Mt. 24:37-41).
This matches perfectly with the events at will occur at the "end of the age" as revealed in the "parable of the tares of the field" (Mt.13:36-43). There the Lord reveals that at the "end of the age" there will be a harvest of the whole earth, and the angels will gather out of the world "all things that offend and them who do iniquity" leaving the righteous to "shine forth as the sun in the kingdom".
"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth" (2 Tim.2:15).
As "workman" studying the word of truth we should be diligent in separating the truth from fiction. We should become as detectives in our approach to understanding God's revelation to mankind. When a detective is confronted with the task of attempting to solve a crime he first searches for the "best evidence" available. And there can be no doubt at all that the best evidence in regard to the events of "end of the age" is the Scriptual facts that demonstrate that at that time there will be a judgment upon the whole earth. Since no harvest has yet occurred upon the whole earth then it is evident that that the "end of the age" remains in the future. The preterists have yet been able to answer these verses in a resonsable way but despite this they continue to mislead others into believing that the "end of the age" has already occurred.