One way to look at it…humility.
According to the Catechism of the Catholic Church paragraph 1719, “The Beatitudes reveal the goal of human existence, the ultimate end of human acts: God calls us to his own beatitude.” And, in paragraph 2546 “…The Beatitudes reveal an order of happiness and grace, of beauty and peace." Thus, the first of the beatitudes, “Blessed are the poor in spirit, for their’s is the Kingdom of Heaven” is the first in the order of “happiness and grace”. What does it actually mean to be “poor in spirit”? How is being “poor in spirit”, at the same time, both revealing of the goal of human existence and God’s own beatitude?
Strictly by dictionary definitions, being “poor” means that one lacks sufficient resources to live a normal standard of life, and, “spirit” is the qualities forming the character of a person. The phrase “poor in spirit” means one who lacks sufficient resources to live to the normal standard of character. How does this make us “blessed”? Coming to the realization that on one’s own one lacks sufficient resources to be a person of good character is the first step in realizing that we need God. On our own we can do nothing. The Kingdom of Heaven belongs to those who realize that they need God, that they must depend on Him to provide the resources to live a right moral life, to those who have faith, trusting in Him to provide those resources. To those who accept these resources to live a right moral life they are not merely just covered in Jesus’ righteousness but actually provided the resources to improve one’s character and be righteous through, with, and in Him. Blessed are the poor in spirit for theirs is the Kingdom of Heaven.
When we start seeing this beatitude and praying that God give us the resources to heal our character we then mourn. We mourn for our sinful lives, all of the times we failed to choose the good and sinned against God. We mourn for the state of the universe, fallen, that man continues to offend God. It is a deep ache in our souls that brings us to tears. We repent of those ways and resolve to turn to Him again, in a deeper more full way. We start to change, to become humble, praying and listening, sensing what is true and good. Desiring to live the way He desires. The cares of the things of the world lessen. Things that seemed so important no longer are. Our emotions and desires are more and more tamed. We meekly accept His will as we understand it. Blessed are the meek!
The beatitudes reveal an order of happiness and grace. None are possible without the first and hinge on the development of that one.