Some people think the resurrection already happened in the first century, but if that is the case then it would of been the end back in the first century, and the saints would be in the New Jerusalem.
Some people think the millennial reign is spiritual, but if that is the case then why is it 1000 years when Jesus has been ruling ever since He ascended to heaven which is more than 1000 years, for He said all power was given to Him in heaven and earth, and He is the head of all principality, and power, and how is Jesus ruling on earth if people were still disobedient from the time of the first century until now.
1Co 15:23 But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming.
1Co 15:24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
When the resurrection happens it is the end, and all authority and power is put down on earth, but there is still authority and power on earth among the wicked over other people, so the resurrection could of not happened in the first century.
Luk 13:25 When once the master of the house is risen up, and hath shut to the door, and ye begin to stand without, and to knock at the door, saying, Lord, Lord, open unto us; and he shall answer and say unto you, I know you not whence ye are.
Mat 25:10 And while they went to buy, the bridegroom came; and they that were ready went in with him to the marriage: and the door was shut.
Mat 25:11 Afterward came also the other virgins, saying, Lord, Lord, open to us.
Mat 25:12 But he answered and said, Verily I say unto you, I know you not.
Mat 25:13 Watch therefore, for ye know neither the day nor the hour wherein the Son of man cometh.
Rev 20:6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
Rom 11:25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
Rom 11:26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
Rom 11:27 For this is my covenant unto them, when I shall take away their sins.
There is only 2 resurrections, one of the saints, and one of the dead after that, and when the resurrection happens then no Gentile can be saved after that, but the Gentiles still have salvation available to them for Israel is still blinded in part, for Israel is blinded in part until salvation is no longer available to the Gentiles.
So the resurrection could of not happened in the first century.
Zec 14:9 And the LORD shall be king over all the earth: in that day shall there be one LORD, and his name one.
Zec 14:16 And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the feast of tabernacles.
Isa 11:6 The wolf also shall dwell with the lamb, and the leopard shall lie down with the kid; and the calf and the young lion and the fatling together; and a little child shall lead them.
Isa 11:7 And the cow and the bear shall feed; their young ones shall lie down together: and the lion shall eat straw like the ox.
Isa 11:8 And the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice' den.
Isa 11:9 They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the LORD, as the waters cover the sea.
The millennial reign is on earth when the heathen shall not acknowledge any other god, or religious figure, but Jesus, and they are all going by the truth of God, and the heathen have to go up year after year to Jerusalem to worship the LORD.
And when this happens God has ended all sin on earth, but there are still people sinning on earth, and that never occurred in the past where the whole earth only acknowledged the LORD, and no falseness.
It is an improper foundation that the resurrection happened in the first century, and that Jesus will not rule on earth in the future, and they try to fit scriptures in to that improper foundation.