Hence, the narrator will not be caught or no one will mind his actions. He is enjoying looking at the scene, when the lovely white snow flakes are falling from the sky and covering the farm land. He is engrossed with this sight and loves to stay there forever.
But then suddenly another thought encompasses the narrator. He is now thinking that his gesture may not be understood by the horse on which he was travelling. Since this is not a normal action done by the narrator so it might get baffled as to what his owner is doing standing there in so cold.
Moreover, the horse might be thinking that there is no farm house near to the area where they are currently standing. It means that there is no place nearby where they could halt for some time, to rest or to let the snow fall stops. Hence, there is no reason to stay there, and they should rather move from there. There is only a frozen lake and these dark woods around, which make the sight all the more dark and fearful. They should ideally move from there as soon as possible, before it gets darker or before the snow fall makes it tougher to move from there. The narrator states that it seems to be the darkest evening of the year. This states that it is late evening and the woods or the forest is really seems very thick. The winter season and snowfall makes it all the more chilled. There seems no warmth from any corner of the surroundings.
In the next stanza the narrator describes the actions by his horse. The horse is wearing a harness bell in his neck. Now, when the horse understands that it is unusual to stand there for long and they should move and reach back to home as soon as possible, it shakes his neck so that the quietness is disturbed by the sound of his harness bell. He basically wants to signal his owner that is the narrator when it sees him to be frozen at the sight of the snow fall on the woods. The horse feels that there seems to be some mistake by the owner to be there. There is quietness in the area. The only sounds are of the winds and the snow flakes falling. This long silence is broken by the sounds of the horse harness bells. This signal is to move ahead, to go to his house.
The narrator finds the woods to be lovely and beautiful. He can see that it is dark and deep yet very attracting and he wants to stay there forever looking at how the snow flakes fall on the woods. But he cannot do what he desire to do. He has to move ahead, since he has many responsibilities to fulfill. He had made promises to someone, seems to be his family members, it is his obligation to fulfill those promises. Moreover, the way that he has to travel is also a lot.
This shows that he is very far off from his house, and it is important to move and reach his house before it gets too late. The narrator says that he have to travel many miles to reach his destination before he sleeps. Sleeps here denotes that before he gets tired off travelling, tired of physical tiredness or the deep meaning if sleep may be that before he retires to death, there are lot of responsibilities he has to undertake.
The gist of the poem seems to be that the poet is deeply sad and deserted. He seems to have failed in his endeavors and still have much more responsibilities in his life towards himself and his family. He knows that he has a long way to go and the time with him is less.