As with vv. 153, 154, the psalmist’s plea is very simple and clear. We find it in vv. 156 and 159:
156 “Great is your mercy, O LORD;
give me life according to your justice.
…
159 Consider how I love your precepts;
preserve my life according to your steadfast love.”
He wants to live; he wants to survive; and he is begging God for life.
Now his life is under threat evidently because he was faithful to the Torah and probably not a little courageous in pointing out that others were not faithful to the Torah. His compassion for his enemies is well known.

Perhaps our backs are against the wall because of health or because of age or because we’ve done something unwise; maybe we are asking God to bail us out. We may even think we deserve our backs to be against the wall.
Still, the one committed to God is encouraged by this psalm to face God, petition God, and appeal to God’s saving mercies on the basis of God’s covenant faithfulness. And to do so not only that basis but also because we have ourselves been faithful.
The psalmist wants to be delivered because God is just — which means God will render judgment in favor of the weak and oppressed and poor and faithful. And because of God’s steadfast love … for the same group. Those who love the precepts of the Lord, who delight in his will and long to do it.