Or HaChaim on Numbers 22:22/אור החיים על במדבר כ״ב:כ״ב

1 ויחר אף ה׳…כי הולך הוא, G'd's anger was kindled that he went, etc. The Torah emphasises the word הוא, "he." G'd's anger was caused by the manner in which Bileam rose early in the morning, saddled his ass, and did not even tell the delegates of Balak that G'd had given permission for him to go. The words וילך עם שרי מואב speak volumes. They mean that Bileam and the delegates were on the same wavelength, that they shared the same objective. Bileam made it plain that he went along on his own initiative.

2We may also glean another insight from the remarks of the Zohar Chadash page 168 on the words וילך שפי in 23,3. According to the Zohar this meant that Bileam isolated himself in order to draw down to him the forces of negative spirituality, impurity. When G'd observed that Bileam isolated himself from the emissaries of Balak this was a sign that he prepared himself to do as he pleased. The fact that he had his two lads with him would not interfere with his attempt at solitude as these lads were part of his regular retinue and he would always do "his thing" in their presence. G'd immediately realised Bileam's intention and this is what caused His anger. The words הולך הוא also convey to us that Bileam would have been ready to curse the Jewish people even if Balak had never asked him to do this and offered to pay him for his efforts. He thereby revealed his innate hatred of the Israelites and all this combined to arouse G'd's anger.

3ושני נעריו עמו, and his two lads with him. Why did the Torah have to tell us this insignificant detail? Tanchuma on our verse says that the Torah taught us rules of proper conduct by mentioning the fact that Bileam as befits a man of his stature did not travel without his own assistants. Even if we accept this, why didn't the Torah mention this detail before telling us that G'd's anger was aroused at Bileam, and that the ass had already been made G'd's emissary to be his adversary? We may understand this in light of Berachot 43 that when one travels in a threesome one will not become aware of destructive forces in one's path nor will one be attacked by such forces. In this instance, seeing that Bileam had become aware of the destructive force arraigned against him, we must understand why he did not become its victim. Our verses explain why Bileam had not recognised the danger himself as well as why he was not harmed by it. The answer is that Bileam together with his two lads formed such a threesome as is mentioned in the Talmud.