Charles Ellicott Commentary Daniel 11:9

"And he shall come into the realm of the king of the south, but he shall return into his own land." — Daniel 11:9 (ASV)

The king of the south.— According to the Hebrew text, these words are in the genitive case (so Theod. Jer.), though the English Version is supported by the Septuagint. In this case the meaning is, “The king of the north shall come into the kingdom of the southern king,” and then shall return to his own land—i.e., the north—apparently without gaining any advantage.