Kings aren't often thought of as needy and poor. I don't often think of myself as needy and poor. Somewhat wanty, to be sure. Not as rich as I'd like to prove I can be without being a snob, absolutely. But it would be senseless for me to claim that I am materially needy or poor.
I can use the old spiritualizing trick and say that I am, or am at least trying to be, poor in spirit. (If I had to, I could probably even mumble up something about being needy in spirit, whatever that might mean.)
But I have to be careful if I talk in terms of being (either actually or potentially) poor in spirit, because being poor in spirit is a good thing for me to be. If this is what I have in mind as I pray Psalm 86, then with the first verse --
Incline thy ear, O Lord, and hear me: for I am needy and poor --
I am saying, "Listen to me, Lord, because I am good and virtuous." In other words, "Because I deserve it." And surely the Psalmist didn't intend that; he goes on to say (in v. 5) that God is "plenteous in mercy." If I am asking for something I deserve, that's a matter of justice, not mercy.
So whatever sort of spiritualizing of poverty and need I do, it shouldn't be the kind that turns them into virtues. (On the other hand, I don't want to turn them into vices, either. "I haven't been storing up treasure in heaven, so listen to me," doesn't make any sense at all.)
Hence it is that in the attainment of the perfection of charity the first foundation is voluntary poverty, whereby a man lives without property of his own....
This is as opposed to using property, as a monk might use a cell in a monastery.
Now, what spiritual property can we be said to own? What do we have, spiritually speaking, that belongs to us by right, that we can do with as we please, that cannot with justice be taken from us?
Strictly speaking, nothing.
Oh, we can talk about merit and such, but even so, "With regard to God, there is no strict right to any merit on the part of man." The claim we have on spiritual goods exists solely and entirely because God has freely promised them to us.
We are all radically poor in spiritual things. We ourselves possess no spiritual good, and are completely dependent upon God to be able to use the least of them.
What about material goods? I doubt there's a reader of this post (including mendicants) who doesn't possess some sort of physical property.
Or do we? Sure, possession of property is a positive right, even a natural right. But "with regard to God"? No. You can't take it with you, and there's no injustice in that. The LORD gives and the LORD takes away; blessed be the name of the LORD!
It is wisdom, then, to see that, before God, everyone is needy and poor. This takes away nothing from those who suffer need and poverty before men, nor should it be any great comfort for those who don't.
The point is, that when I pray Psalm 86, I don't need to gin up feelings of need and poverty or to imagine what it would be like to be Job on the ash heap. It would suffice for me to understand that, whether I feel that way or nor, I really and truly am needy and poor before God, not just spiritually but also materially. This fact is why I hope for God to incline His ear and hear me. If He doesn't, there's nothing I have that I might not lose the use of.
Thinking about that for a little bit will encourage me to ask that God hear me with more sincerity than I would if I think of myself as fat, dumb, and happy with all my material (and spiritual) property. And that, in turn, will reinforce my understanding of myself as needy and poor, which should reinforce detachment, which would likely result in a reduction in the property I own according to natural and positive law (if not in literal, legal poverty).