John 5:25 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.
5:26 For as the Father hath life in himself; so hath he given to the Son to have life in himself;
5:27 And hath given him authority to execute judgment also, because he is the Son of man.
5:28 Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice,
5:29 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.
In verses 28 and 29 Jesus refers to the two resurrections. The resurrection of the righteous at the beginning of the thousand years, and the resurrection of the lost who meet their doom at the end of the thousand years.
In verse 25 Jesus is obviously referring to the first resurrection. The resurrection of the righteous. When I study with people about what happens when you die, I like to conclude with this verse and an appeal. I share that we can get so use to listening and responding to the voice of God, that we will even hear His voice in the grave. Some though will be so used to ignoring His voice, that they will sleep right through the first resurrection. I appeal to them to spend their life listening and responding to the Word of God. Then they will be so tuned into His Word that one day, if they die, His voice will wake them from the grave.