"So this is the moral of my ode: twice beautiful is beauty and what is good doubly good when it is a case of two woolen socks in wintertime."
The poet states that his moral is that something is twice as beautiful, twice as good, when, specifically, it is two warm socks in the winter. But to go further, one could say that the moral of this is to appreciate the little things in life...or depending on your point of view or your economic situation, appreciate everything you have, especially a good pair of socks that will protect your feet from the cold.
I think he is celebrating the ordinary things in our everyday existence - if we're lucky enough to have those things. For people not fortunate enough to have warm socks in the winter time, maybe it is a call for us to not be selfish and to help people out who are in need.
Check the links below, especially the one about his themes, for more information. Good luck!