What does Judges 16:19 mean?
Delilah knows Samson has finally told her the truth about the source of his supernatural strength (Judges 16:5–6; 15–17). If his head is shaved, he will become no stronger than any other man. She has signaled her sponsors, Philistine noblemen, to prepare to capture their hated enemy.Now Delilah manages to get Samson to sleep, apparently with his head on her lap. This is something of a mirror image of when Jael, a woman loyal to Israel, tricked a powerful enemy man into sleeping, then destroyed him (Judges 4:17–21). When Samson is fully asleep, Delilah summons a helper to shave off his hair. Scripture does not explain why Samson failed to wake up, but it's likely he was drugged or drunk. Some commentators suggest that God caused Samson to remain asleep to accomplish His purpose; Delilah's cunning makes it likely she'd take deliberate steps to prevent Samson from noticing what was happening until it was too late.
Once Samson's hair is gone, Delilah begins to "torment" or "subdue" Samson in some way. That might mean tying him up, much as she'd done before (Judges 16:9, 12, 14). Samson's strength had already evaporated before he knew it. When he awakes to hear her familiar warning, he will be shocked to realize he's weak, and that God's power has left him (Judges 16:20).