Daniel 9:26-27 says, "And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined. And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate."

I have thought about a lot of different possibilities as to what covenant is confirmed for 1 week of 7 years in Daniel 9:27 and who confirms it with many for 1 week which would be either the Messiah Jesus Christ or the Antichrist.  If it was the antichrist then he would have to confirm a covenant with the Jewish people at the beginning of 7 years of the tribulation period & allow them to resume their animal sacrifices. Then their daily animal sacrifices would have to be taken away in the midst of 7 years which would be the beginning of the Great Tribulation period of 3 1/2 years.

How does the Messiah Jesus Christ confirm the covenant for 1 week in Daniel 9:27? At the beginning of His ministry on earth of 3 1/2 years after He was tested for 40 days in the wilderness by Satan, He went into the synagogue according Luke 4:16-21. (It must have been the beginning 1st year of 7 years (week of years) on the Hebrew Civil calendar that begins on the Feast of Trumpets.) He then preached the following scripture from Isaiah 61:1-2 according to Luke 4:18-21 which said, "The Spirit of the Lord is upon me, because he hath anointed me to preach the gospel to the poor; he hath sent me to heal the brokenhearted, to preach deliverance to the captives, and recovering of sight to the blind, to set at liberty them that are bruised, To preach the acceptable year of the Lord."  He then closes the book of Isaiah, and in Luke 4:21 He says, "And he began to say unto them, This day is this scripture fulfilled in your ears."  

However, there is a slight difference between Luke & Isaiah because Isaiah 61:1-2 says, "The Spirit of the Lord GOD is upon me; because the LORD hath anointed me to preach good tidings unto the meek; he hath sent me to bind up the brokenhearted, to proclaim liberty to the captives, and the opening of the prison to them that are bound; To proclaim the acceptable year of the LORD, and the day of vengeance of our God; to comfort all that mourn;"  Jesus leaves off the 2nd part of the verse about the day of vengeance of our God; to comfort all that mourn" because it is not taking place at that time. It's part of the Great Tribulation period of 3 1/2 years.  The "good tidings" of Isaiah 61:1-2 are also the same "good tidings" of  Isaiah 52:7 ".. good tidings of good, that publisheth salvation;"   When Jesus was born, the "good tidings of great joy" that Luke 2:10-11 spoke of which was to be all people "For unto you is born this day in the city of David a Saviour, which is Christ the Lord."  

However, now is the acceptable year to accept Him (Jesus Christ) as the Messiah who would be their Savior.  The word Christ means "anointed one" which is the same meaning of Messiah so He is telling them in Luke 4:16-21 that He is the Messiah, the anointed one who God anointed to preach the gospel, and His gospel will eventually be preached to every nation.  He as their Savior will set people free that are captives of sin by shedding His blood and dying on the cross for our sins which is the everlasting New Testament blood covenant of salvation and eternal life.  The Messiah is the one described in Isaiah 53 who was wounded for our transgressions, who was cut off from the land of the living, and His soul was an offering for sin.  The everlasting covenant that Jesus confirmed with many is the everlasting covenant that God, the Father had Isaiah prophesy about 700 years before Jesus Christ was even born which would be the New Testament blood covenant. Is this not the everlasting covenant of Isaiah 61:8 & Isaiah 53? However, Jesus died 3 1/2 years after confirming the everlasting New Testament blood covenant which took away the animal sacrifice for sin since He was the sacrifice for sin.  That leaves 3 1/2 years left in the week of years which is 7 years.  So at the time of the Great Tribulation period of 3 1/2 years Jesus Christ confirms the New Testament blood covenant with many for the rest of the remaining 3 1/2 years left in the week of 7 years by sending an angel to preach the everlasting gospel so that they too can be saved according to Rev. 14:6-7.  And He also sends another angel to warn them about not taking the mark of the beast because that was not in the gospel.(Rev. 14:9-11.)  In my opinion, that is how He confirms the covenant with many for 1 week or 7 years.  The everlasting gospel teaches repentance, salvation, and the everlasting blood covenant which is the New Testament blood covenant.

Rev. 14:6-7, "And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people, Saying with a loud voice, Fear God, and give glory to him; for the hour of his judgment is come: and worship him that made heaven, and earth, and the sea, and the fountains of waters."

Isaiah 49:8-9, "Thus saith the LORD, In an acceptable time have I heard thee, and in a day of salvation have I helped thee: and I will preserve thee, and give thee for a covenant of the people, to establish the earth, to cause to inherit the desolate heritages;That thou mayest say to the prisoners, Go forth; to them that are in darkness, Shew yourselves. They shall feed in the ways, and their pastures shall be in all high places."

I also thought about the possibility that the Messiah Jesus Christ could confirm the New Testament blood covenant with many for one week of 7 years by sending the Two Witnesses for 3 1/2 years at the beginning of the 7 year tribulation period to preach the gospel which includes the everlasting New Testament blood covenant, and He then sends an angel at the time of the Great Tribulation of 3 1//2 years to preach the everlasting gospel as well according to Rev. 14:6-7.  However, the problem with that scenario is what sacrifice would He cause to cease in the midst of the 7 year period.  It would have to be the animal sacrifice that just got started 30 days prior to the beginning of the Great Tribulation period of 1,260 days.  However,1290 days is not the exact middle of the 7 year tribulation period.  How does He stop the animal sacrifice in the midst of the 7 years tribulation period while He is up in heaven?  He doesn't have to come down from heaven to stop it as it is a set time that the Lord God determined that it would happen to fulfill Bible prophesy in the scriptures which would be fulfilled by the Antichrist.

Daniel 12:11, "And from the time that the daily sacrifice shall be taken away, and the abomination that maketh desolate set up, there shall be a thousand two hundred and ninety days."

Daniel 9:27, "And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate."