The Gospel of Matthew records five main teaching discourses from Jesus. Matthew 5-7 is Jesus' call to righteousness, which is about doing the will of God. Jesus is teaching his disciples and the multitudes from the mountain.
Jesus begins with what is commonly called The Beatitudes which are the blessings of God (Matt.5:1-12). The Latin word for "blessed" is beati.
God blesses those who are poor and realize their need for him, for the Kingdom of Heaven is theirs.
God blesses those who mourn, for they will be comforted.
God blesses those who are humble, for they will inherit the whole earth.
God blesses those who hunger and thirst for justice, for they will be satisfied.
God blesses those who are merciful, for they will be shown mercy.
God blesses those whose hearts are pure, for they will see God.
God blesses those who work for peace, for they will be called the children of God.
God blesses those who are persecuted for doing right, for the Kingdom of Heaven is theirs.
God blesses you when people mock you and persecute you and lie about you and say all sorts of evil things against you because you are my followers. Be happy about it! Be very glad! For a great reward awaits you in heaven. And remember, the ancient prophets were persecuted in the same way. NLT
In pronouncing these blessings, Jesus is not saying "try hard to live like this." He is saying that people who already are like this are in good shape. They should be happy and celebrate because of the work that Jesus is now doing.
These are not timeless truths about how the world is. Mourners often go un-comforted, the meek don't always inherit the earth, and those who long for justice often find it eludes them in this life. This is an upside-down world. But Jesus is bringing good news with the proclamation of his kingdom. No matter what our condition, God is on the move. A new covenant is about to be put in place. New promises are being made. God's kingdom is near. We can enter it and live under it's rule right here, right now. That's good news.