Thrust them thro' — Phineas was himself a man in great authority, and did this after the command given by Moses to the rulers to slay these transgressors, and in the very sight, and no doubt by the consent of Moses himself, and also by the special direction of God's spirit.
Related Commentaries of Numbers 25:8
Numbers 25:8
8 And he went after the man of Israel into the tent, and thrust both of them through, the man of Israel, and the woman through her belly. So the plague was stayed from the children of Israel.