The virtues celebrated in the Beatitudes are foreign to the culture of the United States, which is typically one of excess and materialism. It is strange to think that the poor in spirit will inherit the kingdom of heaven, the mourning will be comforted, and the meek shall inherit the earth.
Those who hunger and thirst for righteousness will be filled (Mt 5:6).
Look to the Old Testament prophet Amos for a precursor:
“Behold, the days are coming,” declares the Lord God, “when I will send a famine on the land— not a famine of bread, nor a thirst for water, but of hearing the words of the Lord. They shall wander from sea to sea, and from north to east; they shall run to and fro, to seek the word of the Lord, but they shall not find it.
“In that day the lovely virgins and the young men shall faint for thirst. Those who swear by the Guilt of Samaria, and say, ‘As your god lives, O Dan,’ and, ‘As the Way of Beersheba lives,’ they shall fall, and never rise again.” (Amos 8:11-14)
God is promising to send a time when his word is going to be scarce. People will want to hear a word from him, but nothing will be found. And people who live by false gods (or false versions of God) will be destroyed never to rise again.
People try to find fulfillment in the false gods they make for themselves all the time. Whether that god be money or fame or power, or searching for all of the answers to the Big Questions in nature itself (atheism), these gods ultimately never satisfy the thirst.
Looking at Psalm 63, we can see what happens to those who hunger and thirst for righteousness from the One True God:
O God, you are my God; earnestly I seek you; my soul thirsts for you; my flesh faints for you, as in a dry and weary land where there is no water. So I have looked upon you in the sanctuary, beholding your power and glory. Because your steadfast love is better than life, my lips will praise you. So I will bless you as long as I live; in your name I will lift up my hands.
My soul will be satisfied as with fat and rich food, and my mouth will praise you with joyful lips, when I remember you upon my bed, and meditate on you in the watches of the night; for you have been my help, and in the shadow of your wings I will sing for joy. My soul clings to you; your right hand upholds me. (Ps 63:1-8)
Those who seek after God in earnest always find him, and always find fulfillment in him. C.S. Lewis once wisely stated that God cannot grant joy apart from himself, as there is no such thing.