Blessed are those who hunger and thirst for righteousness, for they shall be satisfied. Matt. 5:6, RSV.
With the fourth beatitude we have reached a major turning point. The first two exemplified a turning away from our human weakness and sin, while the third expressed the Christian's humility in light of that weakness. The fourth, by way of contrast, is a turning toward the positive aspect of Christianity. It is a hungering and thirsting to be right with God and to be like Him.
Thus the Christian life is more than a mourning over past sins. It is also an intense desire for present and future righteousness.
The fourth beatitude is one of the great promises of the Bible. Those who hunger and thirst after righteousness "shall be filled" (KJV). It does not promise "may be" filled, but "shall be." That is the good news that stands at the focal point of the New Testament.
Righteousness is a word with more than one meaning. In the fourth beatitude it implies both the lofty height of being right with God in relationship and of being like Him in character.
Humans have failed dismally in both endeavors. Paul puts it succinctly when he notes that "all have sinned, and come short of the glory of God" (Rom. 3:23). Recognition of that fact in our personal journey is what poverty of spirit and mourning are all about. Those whom the Spirit leads will have a deep sense of unworthiness that they are powerless to do anything about. It is in the light of that utter hopelessness that Paul rejoiced that we "are justified [or counted righteous] by his grace as a gift" (verse 24, RSV).
But the positioning of the fourth beatitude between those dealing with people's relationship to God (Matt. 5:3-5) and those highlighting their responsibility to other individuals indicates that righteousness in the Beatitudes is more than mere justification by faith. It also implies being right with God in character, as indicated by the fact that those who receive His justifying grace God then immediately sends out to serve the world by being merciful (verse 7).
Thus being filled with righteousness relates to both justification and sanctification. The gospel of Christ not only saves us from the penalty of sin but also from its ruling power in our daily life. And in place of being a gossiper and hateful, God wants to make me a peacemaker (verse 9). In place of lust, He desires to infuse me with purity of heart (verse 8). God wants me to be like Him in character. As a result, the word "righteousness" in the fourth blessing spans both halves of the Beatitudes.