In the fourth aliyah the Jews approach the land of Sichon and send a message to its king asking permission to pass through in peace. The King refuses and comes out with an army to attack the Jews. The Jews fight them and win, and occupied their land. Later the king of Bashan, named Og, attacks the Jews. As a result the Jews kill king Og and occupy his land also.

(The fourth aliyah now continues into parsha Balak.)

At this point the Jews have conquered two kingdoms. Now Balak, who was the king of Moav, becomes aware of these victories of the Jews, which mean danger for him and his country. So he sends messengers to Bilam, who is known as a famous non-Jewish prophet, and asks him to curse the Jews. Bilam discusses the matter with G-D and G-D tells him not to curse the Jews.