So the king of the south shall come into his kingdom - That is, into the kingdom of the north, or the kingdom of Syria. This verse seems to be a summary of what had been said about his invading Syria. He would come, on account of the wrongs done to his sister, into the kingdom of the north, and would then return again to his own land.
Related Commentaries of Daniel 11:9
Daniel 11:9
9 So the king of the south shall come into his kingdom, and shall return into his own land.