What the speaker of "Stopping by Woods on a Snowy Evening" by Robert Frost does is very simple; however, why he does it is a bit more complicated. He stops to watch the snow fall near the woods.
Whose woods these are I think I know.
His house is in the village, though;
He will not see me stopping here
To watch his woods fill up with snow.
The second stanza adds a few more menacing (though not terrifying) details which add some depth and meaning to the beauty of this simple scene:
My little horse must think it queer
To stop without a farmhouse near
Between the woods and frozen lake
The darkest evening of the year.
This farmhouse is isolated and the lake is frozen on this, the "darkest evening on the year." Even the horse wonders why they are here, impatient to leave and suspicious that their stopping at this place is a mistake.
He gives his harness bells a shake
To ask if there is some mistake.
The only other sound's the sweep
Of easy wind and downy flake.
The final stanza explains perhaps why the speaker stops, mesmerized by the sight of the falling snow. He has "promises to keep," obligations which he does not hate or fear but which are obviously tedious.
The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.
He has miles to go before he can rest, and he says it again, to add emphasis to the miles and the long wait before he can rest (sleep). But for these few moments, he stops to see the beauty of the snow in front of the farmhouse. It is a respite before he goes back to the things he must do.