The Link

The death of Stephen is clearly referred to as falling "asleep"

And he kneeled down, and cried with a loud voice,
Lord, lay not this sin to their charge.
And when he had said this,
he fell asleep.
Acts 7:60

This is the LINK to the promise in Daniel of the Resurrection

And many of them that sleep in the dust of the earth shall awake,
some to everlasting life,
and some to shame and everlasting contempt.
Daniel 12:2