Rashi on Numbers 22:36/רש"י על במדבר כ״ב:ל״ו

1וישמע בלק AND BALAK HEARD [THAT BALAAM WAS COMING] — He sent messengers to announce this to him.

2אל עיר מואב [AND HE WENT TOWARDS HIM] UNTO THE CITY OF MOAB — to his metropolis, the most important city he had, as much as to say: See what these Israelites wish to exterminate (Midrash Tanchuma, Balak 10).