The weeping angels are aliens with the ultimate defence system. In the sight of any living creature the angels literally cease to exist. They turn to stone. But once they can't be seen, they are deadly.
After the ship containing an angel crashed on the planet of the extinct Aplans, the angel is on the loose. The Doctor, Amy and River Song (and others) are chasing down the angel to neutralise it. To do so they navigate through an underground labyrinth of statues built by the Aplan civilisation.
RIVER: Doctor, there's something - i don't know what it is...Then the Doctor and River realise what it is...
DOCTOR: Yeah, there's something wrong. Don't know what it is yet either. Working on it.
AMY: what's wrong?
RIVER: How could we not notice that!?
DOCTOR: Low-level perception filter. Or maybe we're thick!
The perception filter (one of my favourite Doctor Who concepts) disguises unusual objects such that they appear to be ordinary. The objects are still there - but the filter prevents them from being fully recognised.
It kind of exists in our life too. The things we see - maybe a hundred times, but don't really notice. And it existed in Jesus' time...
When they see what I do,
they will learn nothing.
When they hear what I say,
they will not understand.
And so he encouraged his disciples to be perceptive...
Pay close attention to what you hear. The closer you listen, the more understanding you will be given — and you will receive even more.
Our perception filters may take the form of past hurts, hardened hearts, fears about the answers to the questions we'd rather not ask ourselves, or just the shallow superficial existence that sometimes lures us away from living a more fulfilled life.
Let's try to break the perception filters and receive even more. It may even keep us safe from weeping angels.