Matthew 27:52

and the sepulchers were opened, and many bodies of the saints that slept, arose.

1 Corinthians 15:20

But now, Christ has risen from the dead, the first-fruits of those who slept.

1 Thessalonians 4:14

For if we believe that Jesus died and rose again, so also should we believe that God will, through Jesus, bring with him those who sleep.

John 5:25-29

Verily, verily I say to you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God, and those who hear, shall live.

Acts 7:60

And he kneeled down and cried with a loud voice: Lord, let not this sin stand against them. And when he had said this, he fell asleep. And Saul was well pleased with his death.

1 Corinthians 11:30

For this reason, many among you are weak and sick, and many sleep.

1 Corinthians 15:51

Behold, I declare to you a mystery. We shall not all sleep, but we shall all be changed

1 Thessalonians 5:10

who died for us, that, whether we wake or sleep, we might live together with him.

Treasury of Scripture Knowledge

Summary

And the graves were opened; and many bodies of the saints which slept arose,

General references

Bible References

Many

John 5:25
Verily, verily I say to you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God, and those who hear, shall live.
1 Corinthians 15:20
But now, Christ has risen from the dead, the first-fruits of those who slept.

Slept

1 Corinthians 11:30
For this reason, many among you are weak and sick, and many sleep.
1 Corinthians 15:51
Behold, I declare to you a mystery. We shall not all sleep, but we shall all be changed
1 Thessalonians 4:14
For if we believe that Jesus died and rose again, so also should we believe that God will, through Jesus, bring with him those who sleep.
1 Thessalonians 5:10
who died for us, that, whether we wake or sleep, we might live together with him.

General references

Mark 15:38
And the vail of the temple was rent in two, from the top to the bottom.
Luke 19:40
And he answered, and said to them: I say to you, that if these had been silent, the stones would have cried out.