>>...But I and others, who are right-minded Christians on all points, are assured that there will be a resurrection of the dead, and a thousand years in Jerusalem, which will then be built, adorned, and enlarged, [as] the prophets Ezekiel and Isaiah and others declare. Dialogue with Trypho Chapter LXXX<<
Here Justin Martyr is referring to the New Jerusalem (Rev 21:2) because it is "adorned." He goes on to confirm this by referring to Isaiah (Rev 21:1, Isa 65:17). He probably also alludes to Ezekiel's "millennial" temple which lasts forever (Eze 43:7). There will be a resurrection, and then the expansion of Jerusalem.
>>"For Isaiah spake thus concerning this space of a thousand years: `For there shall be the new heaven and the new earth, and the former shall not be remembered, or come into their heart; but they shall find joy and gladness in it, which things I create. For, Behold, I make Jerusalem a rejoicing, and My people a joy; and I shall rejoice over Jerusalem, and be glad over My people. And the voice of weeping shall be no more heard in her, or the voice of crying. And there shall be no more there a person of immature years, or an old man who shall not fulfil his days. For the young man shall be an hundred years old; but the sinner who dies an hundred years old, he shall be accursed. And they shall build houses, and shall themselves inhabit them; and they shall plant vines, and shall themselves eat the produce of them, and drink the wine. They shall not build, and others inhabit; they shall not plant, and others eat. For according to the days of the tree of life shall be the days of my people; the works of their toil shall abound. Mine elect shall not toil fruitlessly, or beget children to be cursed; for they shall be a seed righteous and blessed by the Lord, and their offspring with them. And it shall come to pass, that before they call I will hear; while they are still speaking, I shall say, What is it? Then shall the wolves and the lambs feed together, and the lion shall eat straw like the ox; but the serpent earth as bread. They shall not hurt or maltreat each other on the holy mountain, saith the Lord.'...[Isa. lxv. 17 to end.]Chapter LXXXI.<<
Now Justin explains the first resurrection as is found in Isaiah.
>>...Now we have understood that the expression used among these words, `According to the days of the tree of life shall be the days of my people; the works of their toil shall abound' obscurely predicts a thousand years. For as Adam was told that in the day he ate of the tree he would die, we know that he did not complete a thousand years. We have perceived, moreover, that the expression, `The day of the Lord is as a thousand years,'[Ps. xc. 4; 2 Pet. iii. 8.] is connected with this subject. And further, there was a certain man with us, whose name was John, one of the apostles of Christ, who prophesied, by a revelation that was made to him, that those who believed in our Christ would dwell a thousand years in Jerusalem; and that thereafter the general, and, in short, the eternal resurrection and judgment of all men would likewise take place. Just as our Lord also said, `They shall neither marry nor be given in marriage, but shall be equal to the angels, the children of the God of the resurrection.'[Luke xx. 35f.] Chapter LXXXI.<<
In this section Justin refers to the first resurrection in which men shall be equal to the angels (Luke 20:35). Those in the first resurrection need not fear the second death (Rev 20:6). It is the new creature that is resurrected (2 Cor 5:17). The eternal resurrection of all men then takes place. The first resurrection is to the New Jerusalem, the Jerusalem above(Gal 4:26), which doesn't descend until Revelation 21. The first resurrection is not a bodily resurrection on the present earth, as is the claim of premillennialism. That is not the claim of the chiliasm of Justin, Irenaeus or Barnabas, and probably not the claim of Papias either. However, Irenaeus spends half of Book V Against the Heresies, explaining that the resurrection in the seventh day is bodily. That is in the new heaven and earth, not the present earth. It is the Gnostics who promise "super-celestial blessings" rather than a bodly resurrection.
I think the reason this is confusing to us today is when a thousand years is mentioned we immediately think of Revelation 20:1-7. We don't understand the same relationship of the consumation to creation that the early church fathers did.