John Calvin Commentary Numbers 24:10

"And Balak`s anger was kindled against Balaam, and he smote his hands together; and Balak said unto Balaam, I called thee to curse mine enemies, and, behold, thou hast altogether blessed them these three times." — Numbers 24:10 (ASV)

And Balak’s anger was kindled against Balaam. Since the obstinacy of the wicked is not overcome, so that they submit themselves to God when He seeks to bring their lusts under control, it is inevitable that when they are pressed further, they are carried away by passion.

Thus, Balak, after complaints and protests, bursts forth into impetuous wrath. He rejects and drives Balaam from his presence with reproaches—Balaam, whom he had until then been trying to cajole. For when he strikes his hands together, it is because he can no longer restrain himself.

He is especially indignant because Balaam had not hesitated to bear witness freely and openly to the blessing of the children of Israel, against whom Balak was so full of hatred. For nothing is more galling to kings than when they see private individuals who are not intimidated by their presence.

Because he decides to give no reward to the uncooperative and ill-fated prophet, he blames God, lest he himself should be discredited by this, as if he were ungenerous. And indeed, what he says is true: God had kept Balaam back from honor. Yet he impiously and, so to speak, reproachfully lays the blame on God, and in fact, accuses Him of being the cause of his promise not being fulfilled.