This Lime-Tree Bower My Prison
In prose, the speaker explains how he suffered an injury that prevented him from walking with his friends who had come to visit.
Then, in verse, he compares the nice garden of lime-trees where he is sitting to a prison. He is disappointed about all the beautiful things he could have seen on the walk. He imagines these sights in detail by putting himself in the shoes of his friends. They walk through a dark forest and past a dramatic waterfall. They emerge from the forest to see the open sky and the ocean in the distance.
He thinks that his friend Charles is the happiest to see these sights because he was been trapped in the city for so long and suffered such hardship in his life. The speaker instructs nature to put on a good show so that Charles can see the true spirit of God.
The speaker suddenly feels as happy as if he were seeing the things he just described. This lime-tree bower isn't so bad, he thinks. It has its own beautiful sights, and people who have an appreciation for nature can find natural wonders everywhere. Sometimes it is better to be deprived of a good so that the imagination can make up for the lost happiness.
The speaker tells Charles that he has blessed a bird called a "rook" that flew overhead. He imagines that Charles will see the bird and that it will carry a "charm" for him.