Or HaChaim on Numbers 22:33/אור החיים על במדבר כ״ב:ל״ג

1 כי עתה גם אתכה הרגתי ואותה החייתי. "surely NOW I would have slain you whereas I would have allowed the ass to remain alive." What is the significance of the word "now" in this verse? Bamidbar Rabbah 20,14 on our verse claims that this verse is proof that the ass was killed. We deduce this from the sequence of the words גם אותכה, "you as well," instead of גם הרגתי אותכה. The word NOW indicates that the ass had been killed immediately before this interchange. When the angel said: "I would have let her live," he referred to what had taken place. He had not killed the first time she spoke up which would have resulted in Bileam being killed also, but had waited until the ass had revealed Bileam's spiritual blindness. The word החייתי actually refers to a new activity, i.e. "I have let her live until now." The angel pointed out that he had done something extraordinary. He had been dispatched to hurt both the rider and and the animal he rode. In this instance the rider had been saved by the action of the animal he rode. In this way the word החייתי is justified.