It is an impossible promise to give the moon, and yet the enormity of love can seem impossible to express. It is a declaration of enormous hope and love. The giver willing to sacrifice something or everything.
This premise makes me think of relationships of all forms that I have ever had or no doubt will have. How sometimes I have felt hopeless to address problems of such magnitude I would long to pull the moon down like a miracle could happen if I did and all the wrongs could be righted. All the lost moments recaptured, the chances not taken returned like a gift from the impossible place. I would vanquish all monsters if I could just bring down the moon.