Lucasta, frown, and let me die,
But smile, and see, I live;
The sad indifference of your eye
Both kills and doth reprieve.
You hide our fate within its screen;
We feel our judgment, ere we hear.
So in one picture I have seen
An angel here, the devil there.

Richard Lovelace

http://www.poemhunter.com/poem/to-lucasta-her-reserved-looks-2/