Birds in the branches of a tree, for example, are used in rabbinic literature as a symbol of Gentiles who in the last days will seek shelter in the shade of Israel. (religion-online.org)
Rabbinic literature explains the holiday this way: our Creator is like a host, who invites us as visitors for a limited time, but when the time comes for us to leave, He has enjoyed himself so much that He asks us to stay another day. (religion.blogs.cnn.com)
Moreover, rabbinic literature states in several places that this conclusion to Deborah's song was not composed by the prophetess, but rather was a product of ruah ha - kodesh, a divine inspiration that caused Deborah to conclude her song in this manner. (firstthings.com)