Or HaChaim on Numbers 25:11/אור החיים על במדבר כ״ה:י״א

1 פנחס בן אלעזר, Pinchas son of Eleazar, etc. Why did the Torah have to give us Pinchas' full genealogy here? [the same genealogy has been recorded only 4 verses previously. Ed.] Perhaps the Torah wanted to give his ancestors an honorable mention in this way. Moreover, it is likely that G'd wanted to heal the residual bad feeling that might have existed against Aaron who at the time when he made the golden calf had inadvertently become the cause of many Israelites dying prematurely (compare Exodus 32,35 "G'd smote the people who had made the calf which Aaron had constructed). Now a grandson of Aaron had come and saved many more Israelites' lives than Aaron had ever even indirectly caused to be lost. This is why G'd Himself goes on record saying: "I have not consumed the children of Israel in My jealousy." In order to make all this clear, Aaron had to be mentioned by name. We have been told in Tanna de bey Eliyahu chapter 13 that Aaron rehabilitated himself through teaching the Israelites Torah and performing good deeds. From this you see that in the eyes of the Israelites Aaron had been considered as responsible for the death of those Jews at the time of the episode of the golden calf. The Torah therefore tells us here that Aaron's grandson completed this task of Aaron's rehabilitation posthumously.

2השיב את חמתי, "has turned away My wrath, etc." The Torah may have mentioned this to teach us that once G'd's wrath has been aroused it requires a new merit on the part of His creatures to assuage the attribute of Justice. At the very least, we can assume that this is what Moses thought. G'd explained to Moses that in this instance it had been Pinchas' deed which had succeeded in turning away His wrath. The very word השיב in the causative form teaches that G'd's anger did not abate on its own.

3מעל בני ישראל, "from the children of Israel, etc." This means that once G'd's anger had descended upon them Pinchas succeeded in removing it from the children of Israel. This is a great compliment to Pinchas. In addition the Torah defines the act which Pinchas had performed as one that caused G'd personally a sense of wellbeing seeing that as long as He was angry and jealous it had caused Him sadness and distress.

4בקנאו את קנאתי בתכם, "when he displayed jealousy on My behalf amongst them." Both the apparently superfluous words קנאתי, "My jealousy," and בתכם, "amongst them," are very deliberate. These factors each contributed to giving Pinchas the power to turn away G'd's wrath. 1) Pinchas displayed his personal jealousy on behalf of G'd by endangering his life on account of G'd's honour. This idea is expressed by the suffix ו at the end of the word בקנאו. 2) His jealousy was purely on G'd's behalf, he had no ulterior motive. When man performs a מצוה for absolutely pure motives without the slightest consideration of how the performance of such a good deed might benefit him personally, this is the most beloved מצוה- performance that exists in G'd's eyes. This is why the Torah defines Pinchas' jealousy as "MY jealousy." 3) Pinchas did not do what he did in the confines of his house with no witnesses, but he performed the deed publicly in full view of his whole nation. Sanhedrin 82 describes that Pinchas was surrounded at the time by the whole tribe of Shimon who had surrounded the tent in which Zimri cohabited with Kosbi. This is what the Torah meant when it wrote: "in their midst."

5ולא כליתי, "and I did not consume totally, etc." Why did the Torah not abbreviate this report by writing thus: "בקנאו את קנאתי השיב את חמתי ולא כליתי, "when he was jealous on My behalf he turned away My wrath so that I did not totally wipe out, etc.?

6The Torah wanted to demonstrate that once G'd's anger had been aroused at בני ישראל, the elite of the Israelites, it could not be turned away without the presence of the three factors in Pinchas' deed we just enumerated. As far as saving the Jewish people from total annihilation, it is possible that G'd would have allowed a small portion of the Israelites to survive even if Pinchas' deed had not comprised all the three elements we described. The prayer of a righteous man such a Moses might have sufficed to accomplish this. However, if the Torah had only mentioned that Pinchas turned away G'd's wrath, without adding that G'd did not annihilate the whole people, I would have concluded that all that the action of Pinchas accomplished was the prevention of the complete annihilation of the people.