We are not able to find the specific reference in Revelation that uses those exact words in the King James translation, but we will assume you are referring to verses in Revelation 20:

Revelation 20:5  But the rest of the dead lived not again until the thousand years were finished. This is the first resurrection.

Revelation 20:12  And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.

Revelation 20:13  And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.

In order to understand this concept, we must first explain the plan of God. Then we will see how this concept fits within that context. 

In Gen 2 – God tells Adam that he may eat of all the trees in the garden, except for the tree of knowledge of good and evil.  He is told that "in the day that thou eatest thereof, thou shalt surely die" (Gen 2:17).  For as long as Adam continued to obey God's rule, he would have continued to live in the garden. 

We know that Adam did eventually eat of the tree, and therefore the death sentence came upon him.  In that sense, Adam was dead (under the death sentence), even though the actual death of his physical body occurred 900+ years after he sinned.  In Matthew 8:22, Jesus says "let the dead bury their dead" – which also describes the concept of mankind being considered dead as they are under Adam's the death sentence, .

So continuing to reason on this concept, the living are not reckoned as living until the death sentence is removed. This is the purpose of Jesus' sacrifice – it lifts the death penalty off of mankind.  1 Corinthians 15:22  "For as in Adam all die, even so in Christ shall all be made alive."  We look around today and people are still dying, which means that Christ's sacrifice has not yet been applied to the world, but if Christ died for Adam, then all born in Adam must be able to benefit from Christ's sacrifice. We believe that this benefit is yet future.

Even though Christ paid for Adam's sin (and by extension the world's sin), in order to stay living after the resurrection, the world must also reach the sinless perfection that Adam had originally when he was created.  Otherwise the penalty of death must be exacted again.  (Ezekiel 18:20  The soul that sinneth, it shall die.)  When mankind is resurrected, there will be many weaknesses of character to overcome, and overcoming these will take time and practice.  This is the purpose of this thousand year reign (Rev 20:5) of the mediator of the new covenant (see Jer 31:31-34, 1Tim 2:5, Heb 12:24) is to perfect the world. To teach them to live righteously. Christ will mediate between God and man while Satan is bound (the thousand years) so that world will have every opportunity to come to a knowledge of the truth (1Tim2:4) and become perfect as was Adam before his fall. 

There is much more to God's plan of course, but in trying to stay focused on the specific question, the 'dead' will rise (be resurrected), because all born in Adam will have to come to Christ in order to live.  Some come to Christ in this lifetime and their reward is a 'better resurrection' (Heb 11:35).  Those who are now blinded by Satan will have their  opportunity to come to Christ while Satan is bound. These will not truly live (or be fully alive) until they reach perfection at the end of the thousand years.  Thank God for His wonderful love and mercy, to give all who will another chance at perfect life.