Pompeius’s civic rights have been restored and Horace is celebrating with him. See the blog post with an ancient party scene here and hear the poem with a translation here.
In the “Poscimur” ode, Horace addresses his lyre and claims that, together, they have made a new type of Roman poetry by transmuting Greek originals. The lyre is probably not a real one, any more than this lyre bird is: it stands for Horace’s poetic skill and genius. Hear the poem and follow in English translation here.