I am thinking that the Lord will send a spirit of slumber on his people. The scripture re the 10 virgins say they were all asleep. It also says we are all woken up. So for some reason to make this just and to fulfill scripture he does this thing.
 
I came to this thought after I read in Judges 9:22 how the Lord sent an evil spirit upon a city because of something that had happened in the past. This brought conflict between the judge and the city and judgement for the past sin came.