Or HaChaim on Numbers 31:16/אור החיים על במדבר ל״א:ט״ז

1 הן הנה….בדבר בלעם, "these are the very ones…in the affair with Bileam, etc." We must try and understand what Moses meant when he referred to "these are the very ones, etc." Besides, why was Moses so long-winded in his reference to Bileam and (subsequently) to פעור. The matter will become clear once we understand why both Pinchas and the pious people who had gone with him committed such an error.

2Pinchas and his colleagues reasoned that the women who had played temptresses at the time had acted under duress, only carrying out their husbands' orders. Unmarried girls were similarly under duress having been ordered by their fathers to do whatever they had done to seduce the Israelites. Accordingly, Pinchas did not think that these women were guilty of death. Moses appreciated the considerations which had prompted Pinchas and his soldiers. This is why he pointed out that Pinchas and his colleagues would have been correct if the only thing these women had been guilty of was to cause the Israelites to indulge in illicit sex. However, in addition to their carrying out their husbands' and their fathers' orders respectively, they had committed another sin, one which they committed out of their own free will, namely that of Peor, i.e. getting the Israelites to worship that deity. According to Bamidbar Rabbah 20,23 these women prevailed on the Israelites to perform acts of obeisance to the image of Peor before letting them indulge their carnal desires. For this sin they were guilty of death, and this is what Moses referred to when he said הן הנה, i.e. they themselves (without outside pressure) initiated this part of the seduction. בדבר בלעם, at the instigation of Bileam, i.e. through the advice of Bileam to have the women offer themselves as sexual partners to the Israelites. If you examine the writings of our sages on the subject you will find that they attribute to Bileam only the advice that the Israelites be seduced sexually. Bileam never said that these women were to seduce the Israelites to worship or appear to worship any idols. By refusing to sleep with the Israelites unless the latter had first performed an act of idolatry, these women were guilty of the מעל בשם, the trespass against the Eternal G'd which our verse speaks about.