The Beatitudes is one of the most well-known passages from the Bible, but due to its paradoxical nature, they remain difficult to understand. What Jesus described in the Beatitudes is the result of us being transformed by the cross, becoming meek and poor in spirit and so forth, and thereby being blessed. Such transformation is the work of God, it is not something we can achieve by our own effort.
The poor in spirit are those who delight in the dependence of God. They do not seek wealth, authority, or other resources which create the illusion that they are in control. They delight in the experience of dependence on God.
Those who mourn are those who see others locked in sin and do not know God, and they mourn. These people are those who intercede for others and pray for the world.
The meek are those who, by God's grace have authority over their anger and other passions. But they also have the necessary courage to stand up for what is right and express righteous indignation at injustice.
Those who hunger and thirst for righteousness are those who seek righteousness and the values of God's Kingdom, such as chastity, forgiveness, and mercy. They hunger for God's word.
The merciful are those, who by God's grace, have experienced God's mercy and are equipped to share that mercy with others. They correct the sinner, they do not need to avenge themselves.
The pure of heart are those who are single-hearted, whose heart are free of contrary drives and wishes.
The peacemakers are those who do not just love peace but actually work for it. They strive for righteousness and bring souls to Christ.
Blessed are those who are persecuted for righteousness sake because only false prophets are loved by all. They are hated by the world because they do not belong to the world. The Kingdom of God is theirs.