Coleridge both admires and pities his friend Charles Lamb (the man to whom he dedicates "This Lime-Tree Bower My Prison"). He admires Lamb for living through such hardship and maintaining a "gentle heart," and for being able to integrate his individual problems into a larger harmony of nature. The speaker of "This Lime-Tree Bower My Prison" wants to share the joys of landscape around his cottage with Charles because he knows Charles will appreciate them. It's the same motive that you have when you make a mix full of your favorite songs for a friend – by doing so, you show your confidence in their good taste. The speaker only regrets that he isn't around to observe Charles's reaction to his "Nature Mix," featuring such hits as "The Roaring Dell" and "Richlier Burn, Ye Clouds!"
The speaker wants to act like a surrogate parent to his friend Charles Lamb.
Charles's life experiences have given him a wisdom that far exceeds that of the speaker.