He who listens behind doors

Knows about every conversation Is always there but never present. Listens without understanding, at least not now, not yet. He changes shapes to suit the hour, inconspiciously pushes outlines to face the light of day. You KNOWwhen he is there. Hewho's standing in the hallway. And if you need a certain sign; look at the handle on your door. You see: it is slightly lowered. Or is it just a strange impression?