וַיֹּ֕אמֶר הִנֵּה־נָ֖א זָקַ֑נְתִּי לֹ֥א יָדַ֖עְתִּי י֥וֹם מוֹתִֽי׃
האָט ער געזאָגט: זע נאָר, איך בין אַלט, איך װײס ניט דעם טאָג פֿון מײַן טױט.
Rabbeinu Bahya
ויחר אף אלו-הים, “G’d’s anger was kindled.” G’d was angry because He realized Bileam had gone in order to curse.
ויתיצב מלאך ה' בדרך לשטן לו, ”an angel of Hashem positioned himself on the way in such a manner as to obstruct him.” Bileam had tried to appropriate to himself a vocation which was meant to be exclusively that of the Jewish people, i.e. הקול קול יעקב, “the use of the voice is a use reserved for Yaakov” (Genesis 27,2). In retaliation for this trespass, the angel also made use of a weapon which is not really his own, i.e. the sword, the weapon allocated to Esau, as he was an angel dispatched by the attribute of Mercy. [Had it been an angel dispatched by the attribute of Justice he would have killed Bileam instead of preventing him from carrying out his sinful intent. Ed.]. We find here another demonstration of the principle מדה כנגד מדה, measure for measure.
ויתיצב מלאך ה' בדרך לשטן לו, ”an angel of Hashem positioned himself on the way in such a manner as to obstruct him.” Bileam had tried to appropriate to himself a vocation which was meant to be exclusively that of the Jewish people, i.e. הקול קול יעקב, “the use of the voice is a use reserved for Yaakov” (Genesis 27,2). In retaliation for this trespass, the angel also made use of a weapon which is not really his own, i.e. the sword, the weapon allocated to Esau, as he was an angel dispatched by the attribute of Mercy. [Had it been an angel dispatched by the attribute of Justice he would have killed Bileam instead of preventing him from carrying out his sinful intent. Ed.]. We find here another demonstration of the principle מדה כנגד מדה, measure for measure.