Jesus, when describing death in this age, regularly used the term "sleep" when describing this condition.
After He had said this, He told them, “Our friend Lazarus has fallen asleep, but I am going there to wake him up.”
John 11:11
So did Paul (1 Thess 4:13-14, 1 Cor 15:6, 18-20) and Peter (2 Peter 3:4).
In John's account of the death of Lazarus, Jesus told Martha explicitly that “Your brother will rise again”. (Jn 11:23)
Martha replied, “I know that he will rise again in the resurrection at the last day.” (vs. 24)
So either they talked about this in the past. Or Martha was referencing what would have been common knowledge for a Jew of her day.
But where does this information come from?
There are really only three statements in our OT canon that are somewhat explicit about this.
Here:
Your dead will live; their bodies will rise.
Awake and sing, you who dwell in the dust!Is 26:19
And here:
But I know that my Redeemer lives,
and in the end He will stand upon the earth.
Even after my skin has been destroyed,
yet in my flesh I will see God.Job 19:25-26
Daniel's statement here is a little more explicit:
But at that time your people — everyone whose name is found written in the book—will be delivered.
And many who sleep in the dust of the earth will awake, some to everlasting life, but others to shame and everlasting contempt. Then the wise will shine like the brightness of the heavens, and those who lead many to righteousness will shine like the stars forever and ever.
Dan 12:1-2
There are a few others in Ezekiel, Hosea, and the Psalms, but they are more implicit rather than explicit statements about the resurrection of the dead.
I don't know about you, but I like to know the origin of things. So where do statements like those above come from?
I believe they come from the very first scribe - the seventh from Adam - Enoch.
Read his statements here:
And in those days shall the earth also give back that which has been entrusted to it,
And Sheol also shall give back that which it has received,
And hell shall give back that which it owes.And he shall choose the righteous and holy from among them:
For the day has drawn nigh that they should be saved.
The Elect One Sits On God's ThroneAnd the Elect One shall in those days sit on My throne,
And his mouth shall pour forth all the secrets of wisdom and counsel:
For the Lord of Spirits hath given them to him and hath glorified him.,,,
For in those days the Elect One shall arise,
And the earth shall rejoice,
And the righteous shall dwell upon it,
And the elect shall walk thereon.Enoch 51:1-5
and here:
"Open your eyes and lift up your horns if ye are able to recognize
the Elect One."And the Lord of Spirits seated him on the throne of His glory,
And the spirit of righteousness was poured out upon him,...
For from the beginning the Son of Man was hidden,
And the Most High preserved him in the presence of His might,
And revealed him to the elect.
...
And the Congregation of the elect and holy shall be sown.
And all the elect shall stand before him on that day.
...
And the righteous and elect shall be saved on that day
...
And the Lord of Spirits will abide over them,
And with that Son of Man shall they eat
And lie down and rise up for ever and ever.And the righteous and elect shall have risen from the earth...
And they shall have been clothed with garments of glory,
And these shall be the garments of life from the Lord of Spirits:
And your garments shall not grow old,
Nor your glory pass away before the Lord of Spirits.Enoch 62
Before Enoch was taken, he had his son Methuselah gather all his children for Enoch's final exhortation:
"Hear, ye sons of Enoch, all the words of your father,
And hearken aright to the voice of my mouth;
For I exhort you and say unto you, beloved:"Love uprightness and walk therein.
And draw not nigh to uprightness with a double heart,
And associate not with those of a double heart,
"But walk in righteousness, my sons.
And it shall guide you on good paths,
And righteousness shall be your companion."For I know that violence must increase on the earth,
And a great chastisement be executed on the earth,
And all unrighteousness come to an end:
"Yea, it shall be cut off from its roots,
And its whole structure be destroyed....
And the righteous shall arise from their sleep,
And wisdom shall arise and be given unto them.Enoch 91
This list is by no means exhastive. This theme resonates throughout the entire Book of Enoch!
I believe it is statements like these that were the foundation for statements given by Job, Isaiah, and Daniel.
This theme also resonated in the words of Jesus. Note this response to Martha's statement about a future resurrection of the dead.
Martha said to Jesus, “Lord, if You had been here, my brother would not have died. But even now I know that God will give You whatever You ask of Him.”
“Your brother will rise again,” Jesus told her.
Martha replied, “I know that he will rise again in the resurrection at the last day.”
Jesus said to her, “I am the resurrection and the life. Whoever believes in Me will live, even though he dies. And everyone who lives and believes in Me will never die.”