Luke 12:4
Luke 12:44I tell you, My friends, do not be afraid of those who kill the body and after that can do no more.
("do not fear those who kill the body and after this are not able to do anything more") is read by JW publications as evidence that human enemies have no power beyond physical death — supporting the doctrine that the dead are unconscious and have ceased to exist. The verse is set up as the foil for v. 5; JW commentary then leans on the Gehenna reference in v. 5 as proof of annihilation rather than conscious punishment.
Verse 4 is half a sentence — read it with verse 5 immediately. Jesus is contrasting two categories of fear: human killers (whose power ends at the body) versus the One who has authority after death to cast both body and soul into Gehenna. The whole point of the contrast is that there IS something beyond physical death, and that Jesus treats it as the more serious threat. If death meant annihilation, Jesus's contrast collapses — both human killers and God would simply end you. The verse only works as Jesus framed it if conscious post-mortem judgement is real. Pair with ("the One who can destroy both soul and body in Gehenna") for the parallel form, which makes the body/soul distinction explicit.