ROMANS 15:8 IDENTIFIES WHO  "HE"  IS IN DANIEL 9:27........

Romans 15:8 

"Now I say that Jesus Christ was a minister of the circumcision for the Truth of God to confirm the covenant  promises made unto the fathers."

The ministry of Jesus Christ was confirming the third promise, of the three promises, of the Abrahamic Covenant  made by God "unto the fathers" ie. Abraham, Isaac and Jacob to send the "many" Hebrew prople a Messiah.  He,  Jesus,   was "cut-off in the midst " of the 70th week of Daniel by His  being crucified  by those whom He was sent.   

Daniel 9:27

"And He ( Jesus ) shall confirm the covenant with many for one week ( the 70th Week of Daniel ), and in the midst of the ( 70th ) week He ( Jesus ) shall  cause ( by the shedding of His blood on the cross ) the sacrifice and oblation ( sacrifice of animal blood ) to cease ( being accepted by God for the atonement of sin )... "

That leaves the last three and one-half years, ie forty-two  months , of the 70th Week of Daniel yet to be fulfilled in the future according to :

Daniel 12:6-7

"How long shall it be TO THE END OF THESE THINGS? ( the end of the 70th Week of Daniel )......It shall be for A TIME ,TIMES,  AND HALF A TIME ,   and when  He ( Jesus ) shall have accomplished to scatter the power of the holy people ( by God's  tribulation judgment )  ALL THESE THINGS ( the 70th Week of Daniel )SHALL BE FINISHED."

SO, THERE YOU HAVE IT :

Because the ministry of Jesus was rejected and cut-off by His crucifixion in the midst of the 70th Week of Daniel by the very people to whom God sent a Messiah; God will send them the Devil and his anti-Christ to fulfill the last  3 1/2 year half of the 70th Week of Daniel which is the 42 months  of GREAT TRIBULATION  according to:

Revelation 12:12

"Woe to the inhabitants of the earth.and the sea for the devil has come down to you having GREAT WRATH because he knows that he has but a short time."

Revelation 13:5

".....and power was given to him ( Satan ) to continue FORTY-TWO MONTHS."

The Second Coming of the Lord will end the 70th Week of Daniel after the 42-month last half of the 70th Week is fulfilled. 

According to Your Word, come Lord Jesus !