These are parts of the same burden, and not unlike what was said before concerning Egypt, under the figure of the land shadowing with wings, Isaiah 18:1.
Related Commentaries of Isaiah 30:6
Isaiah 30:6-7
6 The burden of the beasts of the south: into the land of trouble and anguish, from whence come the young and old lion, the viper and fiery flying serpent, they will carry their riches upon the shoulders of young asses, and their treasures upon the bunches of camels, to a people that shall not profit them.
7 For the Egyptians shall help in vain, and to no purpose: therefore have I cried concerning this, Their strength is to sit still.