The strangers shall fade away - Hebrew, "The sons of the stranger." That is, foreigners. The word rendered fade away - נבל nâbêl - means properly to wilt, wither, fall away, as applicable to flowers, leaves, or plants, Psalm 1:3; Psalm 37:2; Isaiah 1:30; Isaiah 28:1. Here it means that those foreign nations would diminish in numbers and in power, until they should wholly disappear. The idea is, that all his foes would vanish, and that he and his kingdom would be left in peace.
And be afraid out of their close places - The word rendered be afraid means to tremble - as those do who are in fear. The word rendered close places means places that are shut up or enclosed, as fortified cities or fortresses. The reference is to their places of retreat, towns, castles, fortresses. The meaning is, that they would find such places to be no security, and would tremble out of them; that is, they would flee out of them in consternation and alarm. The general thought is that of ultimate complete security for himself and his kingdom, or entire deliverance from all his enemies.

The strangers shall fade away - בני נכר beney nechar, the same persons mentioned above. They shall not be able to effect any thing against me; יבלו yibbolu, "they shall fall as the leaves fall off the trees in winter."
And be afraid out of their close places - Those who have formed themselves into banditti, and have taken possession of rocks and fortified places, shall be so afraid when they hear of my successes, that they shall surrender at discretion, without standing a siege. Perhaps all these verbs should be understood in the perfect tense, for David is here evidently speaking of a kingdom at rest, all enemies having been subdued; or, as the title is, when the Lord Had delivered him from all his enemies.

The strangers shall (k) fade away, and be afraid out of their close places.
(k) Fear will cause them to be afraid and come forth from their secret holes and holds to seek pardon.

The strangers shall fade away,.... Like the leaves of trees in autumn, when they fall and perish; to which hypocrites and nominal professors are compared, Jde 1:12;
and be afraid out of their close places; their towers and fortified places, or the rocks and mountains to which they betake themselves for shelter; but, as not thinking themselves safe enough, through fear and dread, come out of them; see Micah 7:17. Some Jewish writers (q) interpret the words, they shall halt or be lame; that is, because of the chains put upon their feet: and so they are expressive of the conquest made of them. The word in the Arabic language signifies to "come out"; and may be so rendered here, and "come out": in 2-Samuel 22:46; it is, "they shall gird themselves", or "come out girt".
(q) R. Donesh apud Jarchi & Abendana not. in Miclol Yophi in loc. to Apollinar. Metaphras.

Close places - Out of their strong holds, where they shall lurk for fear of me.