Put them in fear, O LORD: that the nations may know themselves to be but men. Selah. Put them in fear - שיתה יהוה מורה להם shithah Yehovah morah lahem, "O Lord, place a teacher among them," that they may know they also are accountable creatures, grow wise unto salvation, and be prepared for a state of blessedness. Several MSS. read מורא morre, fear; but teacher or legislator is the reading of all the versions except the Chaldee. Coverdale has hit the sense, translating thus: O Lorde, set a Scholemaster over them; and the old Psalter, Sett Lorb a brynger of Law abouen tham.
That the nations may know themselves to be but men - אנוש enosh; Let the Gentiles be taught by the preaching of thy Gospel that they are weak and helpless, and stand in need of the salvation which Christ has provided for them. This may be the spirit of the petition. And this is marked by the extraordinary note Selah; Mark well, take notice. So the term may be understood.
"This whole Psalm," says Dr. Horsley, "seems naturally to divide into three parts. The first ten verses make the First part; the six following, the Second; and the remaining four the Third.
"The First part is prophetic of the utter extermination of the irreligious persecuting faction. The prophecy is delivered in the form of an Επινικιον, or song of victory, occasioned by the promise given in the fifteenth verse of the tenth Psalm; and through the whole of this song the psalmist, in the height of a prophetic enthusiasm, speaks of the threatened vengeance as accomplished.
"The Second part opens with an exhortation to the people of God to praise him as the Avenger of their wrongs, and the watchful Guardian of the helpless, and, as if the flame of the prophetic joy which the oracular voice had lighted in the psalmist's mind was beginning to die away, the strain is gradually lowered, and the notes of triumph are mixed with supplication and complaint, as if the mind of the psalmist were fluttering between things present and to come, and made itself alternately present to his actual condition and his future hope.
"In the Third part the psalmist seems quite returned from the prophetic enthusiasm to his natural state, and closes the whole song with explicit but cool assertions of the future destruction of the wicked, and the deliverance of the persecuted saints, praying for the event."
Commentary on the Bible, by Adam Clarke [1831].