‘Have mercy upon me, O YHWH;
Behold my affliction from those who hate me,
You who lift me up from the gates of death;
That I may show forth all your praise.
In the gates of the daughter of Zion,
I will rejoice in your salvation.'
Having declared the general position the psalmist now applies it to himself. He is going through great trouble, suffering at the hands of those who hate him, the unrighteous. He asks YHWH to behold his suffering and affliction. In view of Psalms 9:3-4 it may be that we are to see these troubles as internal, enemies in the midst, for there are always enemies within as well as enemies without. But the following verses suggest a further outbreak of trouble from the surrounding nations.
However he is confident that these enemies too will be defeated. For it is YHWH Who shows mercy, it is YHWH Who raises him up when he feels that he is about to die. And he seeks that YHWH will do so now in order that he might show forth all the praises of YHWH, and rejoice in His deliverance. Let the gates of Zion be triumphant that he might rejoice there in His deliverance.
Note the contrast between the gates of death and the gates of the daughter of Zion. He wants to live in public triumph and joy in Jerusalem, with the unrighteous defeated, he does not want to die and go into the gloom of the grave. ‘The gates' were the place where public affairs were carried on, where celebrations took place and where the representatives of the city were regularly to be found. And there in the gates of Jerusalem he will rejoice in God's deliverance, and show forth all His praise. All will know of God's goodness.
Others see these verses as looking back to Psalms 9:3-4 and as indicating his cry to God then, which brought about the deliverance that he speaks of there, and that interpretation would also gain some support from Psalms 9:15-16 which reiterate the defeat of the nations. But the psalm appears to be ongoing and this may rather be a reminder that once one crisis is past another may appear on the horizon, with God being triumphant over all, until at last in the end righteousness triumphs for ever.
‘Daughter of Zion.' An expression only found here in the Psalms but taken up by the prophets later. Zion was the mountain, and her daughter the city built on the mountain, especially important because it was on the mountain which God had chosen. But as always a city also signifies its people.