It may seem strange to write a book of poems which begins with an announcement that you intend to give up writing poetry. Horace, however, is thinking more of content than form when he says that he will no longer be writing any poems. It is true that the form is not quite the same either, as Horace uses heroic hexameters for his Satires and Epistles, which he regards as more serious work than his lyric poetry. The real point that he is making, however, is that he will not now be writing about the trivial subjects associated with lyric verse, such as love and wine. Instead, he will devote himself to philosophy, moral philosophy in particular.
First, Horace justifies his choice to stop writing lyric verse by saying that he has already written plenty and has won his discharge. He compares himself to an old soldier, worn out by campaigning. Then he says that his lyric verse was trivial, nothing but a lot of silly tricks. He now finds himself completely absorbed in the study of philosophy, which is not only more important than poetry but also more interesting and more universally applicable. He then launches into a long paean in praise of his new subject, concluding that a man with a truly philosophical outlook is second only to a god.