The Kedushas Levi on the Erev Rav

The Kedushas Levi, R' Levi Yitzchak of Berditchev, takes note of the following pasuk at the beginning of Balak:

3. Moab became terrified of the people, for they were numerous, and Moab became disgusted because of the children of Israel.

ג. וַיָּגָר מוֹאָב מִפְּנֵי הָעָם מְאֹד כִּי רַב הוּא וַיָּקָץ מוֹאָב מִפְּנֵי בְּנֵי יִשְׂרָאֵל:

"It appears that that which the Scriptures first specifies 'the nation' and afterwards 'the children of Israel' is because that which is known in the midrash and in the Zohar HaKadosh, that the word עם refers to the Erev Rav {mixed multitude, meaning those who converted and joined the Israelites}. And this is  וַיָּגָר מוֹאָב מִפְּנֵי הָעָם מְאֹד, because of the am, the Erev Rav, they feared. For they saw that everywhere Israel dwelt, converts converted to join them, just as the Erev Rav that converted to Israel. Because of this, they feared that the Bnei Yisrael would come to its border, for perhaps from its own nation as well people would convert. And, so that you should not ask why this would bother them, the Scriptures stated, וַיָּקָץ מוֹאָב מִפְּנֵי בְּנֵי יִשְׂרָאֵל, 'and Moab became disgusted because of the children of Israel', that they much hated Israel."