[25:15] 2 sn The passage makes it clear that this individual was a leader, one who was supposed to be preventing this thing from happening. The judgment was swift and severe, because the crime was so great, and the danger of it spreading was certain. Paul refers to this horrible incident when he reminds Christians not to do similar things (1 Cor 10:6-8).
[25:17] 3 tn The form is the infinitive absolute used in place of a verb here; it clearly is meant to be an instruction for Israel. The idea is that of causing trouble, harassing, vexing Midian. The verb is repeated as the active participle in the line, and so the punishment is talionic.