"Blessed are those that hunger and thirst for righteousness, for they shall be filled."
The beatitudes are not a checklist designed for earning or achieving, as if those who are working very hard at good works, will as a result, be rewarded with the blessing of full righteousness.
The beatitudes identify blessings that have already been received. First, God's Grace in Jesus Christ causes believers to desire His righteousness, because their righteousness is 'as filthy rags'. Second, they will be filled all the way to full righteousness in Christ, in the court of Heaven. Blessed indeed!
Matthew 5:3-10
Blessed are the poor in spirit, for theirs is the kingdom of heaven.
Blessed are those who mourn, for they will be comforted.
Blessed are the meek, for they will inherit the earth.
Blessed are those who hunger and thirst for righteousness, for they will be filled.
Blessed are the merciful, for they will be shown mercy.
Blessed are the pure in heart, for they will see God.
Blessed are the peacemakers, for they will be called children of God.
Blessed are those who are persecuted because of righteousness, for theirs is the kingdom of heaven.