Let's follow this thread a little further. Orpheus with his lyre can be viewed as the ur-mask, the archaic arch-persona of the poet; Orpheus can also be seen as the representative figure for the mythical, the poetic word in its own right, per se. The poet is the person devoted to the muse - bonded in a formal relationship with whatever or whoever it is that instigates music & song. The poetic word is language under the sign of that muse - "music" - harmony; it is language fused in a formal bond with art, with beauty.
This is an unfashionable way of thinking; we hardly know what these terms mean anymore. What is the beautiful to us? What is beauty? Think of how we experience it in ordinary things. The encounter with beauty is an end in itself. It is non-utilitarian; it is an experience, an effect not a cause - it is something we undergo, not something we create from nothing. Even in our works of art, where we aim to produce something beautiful, all we can do is aim toward it, labor toward it - and perhaps it will coalesce & appear. We can't will it into being.
There is something a little frightening about our inability to control this dimension (perhaps the "sublime" is actually a sort of psychological projection of this terrifying, unmanageable aspect of beauty). Let us suggest that beauty is fundamentally a "spiritual" phenomenon, where by spiritual we mean precisely that dimension of experience which we can only undergo, which is always a little bit beyond our ken and out of our grasp. (I realize this doesn't really "explain" what I'm trying to get at : but this thread we're following is headed toward that very border of the ineffable, the inexplicable.)
I would like to suggest further that all beauty is embodied beauty. Even abstract mathematical proportions only "make sense" in terms of their extension into dimensions, their applications. It follows then, from our sketch of a definition, that the encounter with beauty happens at the conjunction point of the spiritual and the material - the ineffable and the knowable. Beauty in its very substance is a conjunction of opposites, then - a coniunctio oppositorum.
This brings me back to the duality or agon outlined earlier here, between the Apollonian & the Dionysian. The Apollonian calm, the beautiful order, the harmony represented by Orpheus is rooted in a "passion of undergoing" : the experience of beauty itself, of its paradoxical union of dual worlds. Here we approach the peculiar "stasis" inherent in beauty and in art - Eliot's chinese vase, "still moving" in its stillness. All this reaches back to our own basic and ordinary undergoing of beauty (as a "spiritual" dimension of everyday life). The challenge of the Dionysian, then - the orgiastic glee/rage of the Maenads - can be understood as part of the process (dialectical, conflictual) of the senses' submission to the uncontrollable spiritual power (of beauty). It is natural force submitting to spiritual order.