To lie down — for sleep, rest, death, or sexual intimacy. The euphemism 'to lie with' describes sexual relations. 'He lay down with his fathers' is the standard death formula for kings.
The resting/sleeping/dying range of shakab connects mortal sleep and eternal sleep. The resurrection hope is implicit in texts like Daniel 12:2 where many who 'sleep in the dust' will awake.
Daniel 12:2 is a pivotal resurrection text — shakab used of death, with awakening to follow. Paul's language 'those who have fallen asleep' (1 Thess 4:13-15) draws on this OT idiom of death as sleep.