Those who hunger and thirst after righteousness. That kind of hunger is a character of all the citizens of God's Kingdom. Their supreme ambition is not material, but spiritual. Instead, they set before them, as the Supreme Good, God's Kingdom and God's righteousness. It's moral and social.
Moral righteousness is righteous character and conduct.
And Jesus said that this righteousness must exceed that of the scribes and the Pharisees. It's not merely external conformity to the rules, but it's an inner righteousness of heart and mind and motive. However, But it is social righteousness as well. We hunger and thirst that men and women should be free from oppression and bondage and discrimination. We hunger for the promotion of civil rights, of justice in the courts of law, integrity in business dealings and honor in our home and family life.