Or HaChaim on Numbers 23:7/אור החיים על במדבר כ״ג:ז׳

1 וישא משלו ויאמר, And he began his parable and said: When Bileam noticed that G'd had neither told him what to say nor had He told him not to speak, he thought he had been given permission to speak. This is why be made ready to say what he had in his mind. At that moment G'd twisted his mouth and tongue and forced him to say something quite different. What Bileam said is introduced by the word ויאמר. We may also understand the verse to mean that Bileam abandoned his prepared parable and instead said what the Torah has recorded here. According to Bamidbar Rabbah 20,19 the words מן ארם ינחני בלק must be understood as "Balak dragged me down from a spiritually high level so that I now face destruction." According to this the word וישא may be understood to mean "he raised his voice lamenting that he had become למשל ולשנינה, an example of someone who used to be of lofty stature and now had become an example of how the mighty had fallen."

2We may also understand the verse in terms of the different levels of prophecy we discussed in Beha-alotcha on Numbers 12,6. We had stated there (page 1436) that there are some prophets whose powers of perception are not strong enough to be able to cope with a direct effusion of G'd's message. Such prophets receive the message in the form of a parable. Even Jewish prophets had to receive their prophecies in this fashion. It is not surprising therefore that Bileam, a Gentile, received his prophetic inspiration in the form of parables. When the Torah describes Bileam as וישא משלו, the idea is that he considered prophecy as a burden, משא. The reason for this is the extraordinary emotional stress experienced by the prophet.

3לכה ארה לי יעקב, "come and curse Jacob on my behalf." Inasmuch as there were two categories of Israelites, the righteous and the average ones, Balak had expressed his hope that he could smite at least the average Israelites, the ones described as Jacob as opposed to the righteous who are described as Israel. As to the righteous ones, Balak had expressed the hope to at least drive them out of his proximity. Bileam took his cue from what Balak had requested from him. The word ארה represents a curse of greater intensity than the word זעם, which Bileam reserved for the righteous Israelites. Even Balak had realised that it would be difficult to effectively curse the righteous Israelites.