The 1000 Year Reign (Millennial Kingdom) of Christ in Person on Earth
1Cr 15:23 But each in his own order: Christ the firstfruits; then they that are Christ's, at his coming.
At His coming is before the 1000 years (Rev. 20.4).
1Cr 15:24 Then [cometh] the end, when he shall deliver up the kingdom to God, even the Father; when he shall have abolished all rule and all authority and power.
The end comes after the 1000 years when Satan is finally cast into hell for all eternity.
1Cr 15:25 For he must reign, till he hath put all his enemies under his feet.
He must reign not only now by the Holy Spirit within believers (only believers) and the kingdom of God inside His children today, but also when He returns in Person to step down on the mount of olives (Zech. 14.4) when He returns with His overcomer believers for the 1000 years (Rev. 20.4; Jude 14,15).
1Cr 15:26 The last enemy that shall be abolished is death.
Death and Hades will be cast into Hell (Rev. 20.14) at the end of the 1000 years (Rev. 20.2-7).
1Cr 15:27 For, He put all things in subjection under his feet. But when he saith, All things are put in subjection, it is evident that he is excepted who did subject all things unto him.
All things are not put in subjection yet, and during the millennium there will still be yet some hidden sin as well until the end when Satan is let out for a short while (Rev. 20.7), then cast into the fire.
1Cr 15:28 And when all things have been subjected unto him, then shall the Son also himself be subjected to him that did subject all things unto him, that God may be all in all.
This is when God and the Lamb will be at the center of the new city on the new earth (Rev. 21.3; 22.3,4).