Gregory of Nyssa
He, after being guided by those who brought him to the ruler of the people, is instructed by the voice of the donkey that his path will not lead to success.
And the angel said to him: Why beatest thou thy ass these three times? I am come to withstand thee, because thy way is perverse, and contrary to me:
וַיֹּ֤אמֶר אֵלָיו֙ מַלְאַ֣ךְ יְהוָ֔ה עַל־מָ֗ה הִכִּ֙יתָ֙ אֶת־אֲתֹ֣נְךָ֔ זֶ֖ה שָׁל֣וֹשׁ רְגָלִ֑ים הִנֵּ֤ה אָנֹכִי֙ יָצָ֣אתִי לְשָׂטָ֔ן כִּֽי־יָרַ֥ט הַדֶּ֖רֶךְ לְנֶגְדִּֽי׃
2 Church Fathers comment on this verse
He, after being guided by those who brought him to the ruler of the people, is instructed by the voice of the donkey that his path will not lead to success.
Why does the Lord persist in admonishing Balaam despite his obstinacy and hardness of heart? It is because He desires to do everything possible to instruct the sinner, rendering him defenseless. God even strikes fear into him through the miraculous speech of the donkey and the vision of the angel, so that Balaam might understand the care God has for the people of Israel. It may have also been essential for the dignitaries of Balak, who were with Balaam, to grasp this according to God's will. Some suggest that this angel is Michael, the representative of the people of Israel.
Passages read together with this verse.