‘When my enemies turn back,
They stumble and perish at your presence (face).
For you have maintained my right and my cause;
You sit in the throne judging righteously.
You have rebuked the nations, you have destroyed the unrighteous,
You have blotted out their name for ever and ever.
The enemy are come to an end,
They are desolate for ever;
And the cities which you have overthrown,
The very remembrance of them is perished.'
This could be speaking of David or it could have in mind the current king, but in the end it is the greater David Who is in mind for He achieves the final victory. In each case the king rejoices in the great victories that YHWH has accomplished. He knows that he himself has been victorious because YHWH has been with him. That is why his enemies turned back, fled in panic, and stumbled and perished. They were in the presence of YHWH (‘before the face of YHWH') and could not face Him, and therefore could not stand against God's anointed. For similar descriptions of the effect of God's presence compare ‘you shall make them (your enemies) as a fiery furnace in the time of your presence' (Psalms 21:9), for ‘the face (presence) of YHWH is against those who do evil, to cut off the remembrance of them from the earth' (Psalms 34:16). See also Exodus 14:24.
And, as the Psalm goes on to point out, this is not only what He is like for the king, or even for the people as a whole, but an example of what He will be to each of His people, even to the very lowest (Psalms 9:12; Psalms 9:18). All their unrighteous enemies will be similarly dealt with. The face of God will be with them and in the end all will flee before Him.
‘For you have maintained my right and my cause, you sit in the throne judging righteously.' It is important to recognise that God only acts thus in a righteous cause. It was only because the king was living and judging righteously that he could expect help from YHWH. But because of that, and because God had chosen him, he can then expect help from the Righteous One. God has delivered in this case because the one delivered was accounted worthy. All who walk worthily in a way that is acceptable to God can also be sure that their enemies will finally be defeated, because for them too He is on His throne judging righteously. And this all finally points forward to the triumph of the greater David Who will one day come and triumph in YHWH's name in the day of permanent triumph.
‘You have rebuked the nations, you have destroyed the unrighteous.' This explains why God has given His righteous king, the one accepted as righteous in His sight, the victory. It is because his enemies were unrighteous in God's sight. Thus their final fate was sealed in a way that was to be the inevitable fate for the unrighteous. For the unrighteous there is no future hope, unless they turn from their sins and respond to His mercy.
‘You have blotted out their name for ever and ever. The enemy are come to an end, they are desolate for ever; And the cities which you have overthrown, the very remembrance of them is perished.' The king looks with gratitude at the way that God has dealt with his enemies, and sees in it a guarantee that in the end all the unrighteous must be destroyed. The temporary victory will be followed by the final victory. The finality of it is revealed. Their name will be blotted out (compare Exodus 17:14), they will come to an end and be desolate for ever, and the remembrance of their overthrown cities will perish. This is the only end possible for the unrighteous, unless they return to God.