Numbers 22:22
And God’s anger was kindled because he went: and the angel of the LORD stood in the way for an adversary against him. Now he was riding upon his ass, and his two servants were with him. And God’s anger was kindled because he went: and the angel of the LORD stood in the way for an adversary against him. Now he was riding upon his ass, and his two servants were with him.
God had first forbidden the going, then permitted it only if Balak's men called in the morning, but they did not call and were annoyed at his delay. Balaam could easily have excused himself and avoided going altogether. Instead he set out anyway to overtake the messengers without being called, though he had already recognized his duty to refuse Balak's offer.
He acted against that duty while still professing obedience to God and to be His prophet. His going was double-minded and perverse, following his own inclination to please both God and man while selfishness and covetousness had entered and God was left out of his heart. He was driven by covetous desire for favor, honor, gain, promotion and rewards from God's enemies, by ambition and selfish plans. Such human planning hinders God's work.
Therefore God's anger was kindled because he went against God's will to gratify the Moabites and curse Israel. The angel of the Lord stood in the way as an adversary to oppose, withstand and slay him for his presumptuous folly. He was riding upon his ass with his two servants with him on a way perverse before God.
The donkey saw the angel and repeatedly turned aside, preserving Balaam's life. Balaam, blinded by covetousness, ambition, passion and rage, could not see the divine messenger or the divine intervention. Beside himself with rage he noticed nothing remarkable even when the beast spoke, and he mistreated and cruelly abused the animal that was protecting him.
When the angel revealed himself Balaam was terrified, dismounted, left his beast, and bowed in humility before him. The angel told him he came out to withstand him because his way was perverse, and warned him impressively against gratifying the Moabites. Then permission was given to pursue the journey, because God would glorify His name before Israel's enemies even through presumptuous Balaam by showing that a man of covetous disposition dared not pronounce a curse against Israel for any promises of promotion or rewards. That testimony was important to Israel in order to overcome the Moabites and then overcome the inhabitants of Canaan.
The standing of the angel against Balaam shows that God sees cruelty to animals, protects the helpless beast that Balaam mistreated, and holds people accountable, since helplessness does not make suffering insignificant to Him. It shows that selfish human plans hinder God's work. It shows that God uses angels and divine power to restrain those intent on evil, as an angel likewise met Saul and prevented him from carrying out his purpose against David when Balaam was opposed on his way to curse Israel.
The verse belongs to the episode in which Balak conducted Balaam from one place to another in the vain hope that blessing could be turned into a curse. It illustrates repeated but futile efforts to move one sustained by divine power, since human applause and fear of man are alike powerless against him.