Commentaire sur Les Nombres 23:19

לא איש וגו׳ [GOD IS] NOT A MAN [THAT HE SHOULD LIE] — He has already sworn to them that He will bring them thither and give them as a possession the land of the seven peoples, and you think to slay them in the wilderness?! (cf. Midrash Tanchuma, Vayera 13)

לא איש א־ל ויכזב, "G'd is not like man who deceives, etc." Bileam described two attributes of man on two levels comparing them with parallel attributes of G'd. 1) Man makes promises to people concerning certain matters; 2) man tries to avoid becoming dependent on others in his dealings. Concerning the former, Bileam says that the essential difference between G'd and man is that G'd keeps His promises whereas man often deceives, disappoints the people who have been promised by him. Concerning the second attribute, Bileam says that whereas man may change his mind concerning matters he had planned which did not involve undertakings to his fellow man, he nonetheless is apt to have remorse, to change his mind before executing his plan. Not so G'd. When G'd decides on a course of action He will not change His mind even if such a change of mind does not involve a third party. The examples that Bileam had in mind were twofold. 1) G'd had said (to the patriarchs) that He would establish the Kingdom of Israel and deal favourably with that nation. 2) He had planned to give His Torah to His people, the people He considers holy. This latter plan was something G'd had not revealed as a promise to anyone beforehand. Bileam said that G'd does not renege on either of these two plans of His, i.e. the promises made to the patriarchs, nor to His plan to give the holy Torah to the Jewish people and to guide them to perform the commandments. If Bileam would be allowed to curse the Jewish people, G'd would have to renege on both of these two plans of His! How could He allow this to happen? [the important part of this approach is the transitive use of the word ויכזב, and the intransitive use of the word ויתנחם. Ed.]

לא איש א-ל, G’d is not like man that He could renege so quickly on a blessing just bestowed, seeing that these people have not committed any sin since receiving this blessing.