ויחל העם לזנות, originally, there had been no intention of committing idolatrous acts at all. All that the males had intended was to indulge their libido with the womenfolk who made themselves available. However, these people fell victim to precisely the warning of the Torah in Exodus 34,15-16 of what would happen if Jews would allow the Canaanites to remain in their country and conclude a covenant with them. They would be invited to their social gatherings resulting in their eating forbidden foods, and eventually intermarriage followed by lip service to their gods.

ויאכל העם וישתחוו לאלוהיהן. This was a classic demonstration of how the evil urge works, first suggesting minor infractions of Torah law and then, gradually, suggesting major sins. (compare Shabbat 108)

נגד השמש, so that the people would observe the execution of the idolaters and by not protesting their punishment achieve atonement. This would help them achieve atonement for having sinned by not protesting the sinners’ conduct beforehand.

ותעצר המגפה, for G’d had already decreed previously that all the people who had spurned Him would not see the land of Israel. (Numbers 14,25). [this justifies the letter ה before a מגפה which we had not heard about. Ed,]

בקנאו את קנאתו בתוכם, for having taken G’d’s vengeance in the presence of all the people, so that by their watching what he did and not protesting his deed they would qualify for atonement of their sin for not having protested the sinners at the time when they were about to commit their evil deeds. [compare author on verse 4 in this chapter where he made a similar point explaining the unusual command by G’d to Moses. Ed.]

את בריתי שלום. Peace with the angel of death. We have a similar meaning of this word שלום in Job 25,20 עושה שלום במרומיו, “He makes peace in His lofty regions.” [I assume that the reference is to the fact that the angel of death has no authority in the celestial regions. Ed.] Losses occur only as a result of confrontations by opposites. We find that as a result of this שלום, “peace, or armistice” with the angel of death Pinchas enjoyed an exceedingly long life on earth, more so than any other member of his generation. In fact, he was still serving as priest in the Tabernacle at Shiloh during the civil war between Binyamin and the other tribes. This occurred many years after the death of Joshua and the elders who were Joshua’s assistants. (Judges 20,28) Joshua 24,26 reports these elders as surviving Joshua for many years. If, as is indicated by the Talmud, Pinchas was still alive in the days of Yiphtach (Judges 11,26) he must have been 300 years old by that time. (compare either Bereshit Rabbah 60,3 or Pirke de Rabbi Eliezer chapter 47 on the subject of Pinchas)

תחת אשר קנא לאלוקיו, seeing he had had the courage to fight My fight, I have ennobled him, granting him “peace” [a fitting reward for a noble fight. Ed.]

ויכפר על בני ישראל, seeing that he did what he did in full view of his peers so that they would obtain expiation for not having protested Zimri’s behaviour, he proved himself fit to become a priest whose primary function it is to secure expiation for the sins of their Jewish brethren. As a priest he could continue in the role he had first adopted on this occasion.

ושם איש ישראל המוכה, Pinchas had endangered his own life by what he did in view of the high rank of his victim, one of the 12 princes of the people, as well as a princess from a neighbouring country. [if not for this, the Torah might not have bothered to name the individuals concerned just as it did not name such sinners as the man gathering wood (Numbers 15,33, or the blasphemer Leviticus 24,10. Ed.]