John recorded that the martyrs “lived and reigned with Christ a thousand years” (Revelation 20:4), and this comprises the first resurrection (Revelation 20:5-6), because those who were in the literal graves (Revelation 20:11-12) or who were buried in the sea (Revelation 20:13) didn’t live again, until the end of the thousand years (Revelation 20:5)! What can be understood from this?
John tells us that judgment (i.e. a verdict) was given to those who lived and reigned with Christ a thousand years (Revelation 20:4), but this wasn’t done exclusively for the martyrs. The Lord also determined that all believers, including those still living out their physical lives would live and reign with Christ in heavenly places. Paul told his readers that they had been dead in their sins, but were quickened, i.e. born again (cp. John 3:3; 1Peter 1:23) or raised to life (Ephesians 2:1). In other words, while they walked in the course of this world (Ephesians 2:2-3), they were spiritually dead (Ephesians 2:5), but Christ quickened them and caused their spirits to live so they could sit in heavenly places in Christ (Ephesians 2:5-6; Revelation 20:4). In other words, the death that John tells his readers they were raised out of was spiritual death, so, therefore, the first resurrection occurs for those who were physically alive but dead as far as spiritual things were concerned. They were raised to spiritual life, because they believed and obeyed the Gospel. Notice what Jesus says in the Gospel of John:
Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life. Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live. For as the Father hath life in himself; so hath he given to the Son to have life in himself; And hath given him authority to execute judgment also, because he is the Son of man. Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation. (John 5:24-29 KJV)
Jesus makes a distinction between those who hear and believe him (John 5:24) and those who are resurrected out of literal graves (John 5:28-29). Those who are resurrected out of literal graves are judged according to how they lived (John 5:29), but those, who are given everlasting life in John 5:24, live because they hear and believe Jesus (John 5:25). Moreover, Jesus describes this giving of life on his part as judgment, a verdict, if you will, that the Father had given him to exercise (John 5:27), and this is the same judgment or verdict that was given to those who lived and reigned with him for a thousand years (Revelation 20:4).
Therefore, according to the Apocalypse, the first resurrection has to do only with those who lived and reigned with Christ for a thousand years, and this affected only those living during the first century AD. It had absolutely nothing to do with folks who were physically dead and rose from their graves (cp. Acts 2:29, 34). The resurrection of the righteous and the unrighteous (Matthew 13:30, 36-42) wouldn’t occur until the end of the age (Matthew 13:39, 49) or after the millennium (Revelation 20:12-13).