When mine enemies are turned back, they shall fall and perish at thy presence.
Turned back — Put to flight.
 But the LORD shall endure for ever: he hath prepared his throne for judgment.
But — Though cities and people may perish, yet the Lord abides for ever. Which is sufficient for the terror of his enemies, and the comfort of his church.
 And they that know thy name will put their trust in thee: for thou, LORD, hast not forsaken them that seek thee.
Thy name — Thy infinite power and wisdom, and faithfulness and goodness. The name of God is frequently put for God.
Put their trust — The experience of thy faithfulness to thy people in all ages, is a just ground for their confidence.
 Sing praises to the LORD, which dwelleth in Zion: declare among the people his doings.
Zion — Whose special and gracious presence is there.
People — To the heathen nations.
 When he maketh inquisition for blood, he remembereth them: he forgetteth not the cry of the humble.
Blood — The bloodshed of his innocent and holy ones: which though he may not seem to regard for a season, yet he will certainly call the authors of it to a severe account.
 That I may shew forth all thy praise in the gates of the daughter of Zion: I will rejoice in thy salvation.
Gates — In the great assemblies. These gates he elegantly opposes to the former.
Of — Of the people who live or meet together in Zion. For cities are as it were mothers to their people, and the people are commonly called their daughters. So the names of the daughters of Egypt, Jeremiah 46:11, and of Edom, Lamentations 4:21,22, and of Tyre, Psalms 45:12, are put for the people of those places.
 The LORD is known by the judgment which he executeth: the wicked is snared in the work of his own hands. Higgaion. /*Selah*/.
Higgaion — This is either a musical term, or a note of attention, intimating that the matter deserves deep meditation, or consideration, as the word signifies.
 The wicked shall be turned into hell, and all the nations that forget God.
Forget — That do not regard God, nor his precepts, nor his threatenings and judgments.