And God's anger was kindled because he went, or, "that he was going." כִּי־הוֹלֵךְ הוּא. Septuagint, ὅτι ἐπορεύθη αὐτός. There can be no question that the ordinary translation is fight, and that God was angry with Balaam for going at all on such an errand. It is true that God had given him permission to go, but that very permission was a judicial act whereby God punished the covetous and disobedient longings of Balaam in allowing him to have his own way. God's anger is kindled by sin, and it was not less truly sin which prompted Balaam to go because he had succeeded in obtaining formal leave to go. The angel of the Lord stood in the way. The same angel of the covenant apparently of whom Moses had spoken to the Edomites (see on Numbers 20:16).
For an adversary against him. לְשָׂטָן לוֹ. Septuagint, διαβαλεῖν αὐτόν, Not so much because Balaam was rushing upon his own destruction as because he was going to fight with curses, if possible, against the Israel of God (cf. 2 Kings 6:17; Psalms 34:7).