As with most of the beatitudes that Jesus uttered in his "sermon on the mount," the idea of hunger and thirst as a form of blessedness is at best counterintuitive.
Most of us are used to being satisfied NOW. Food and drink are not just sustenance; they are integral to entertainment and cultural identity: Movies call for a tub of popcorn and a bladder-bursting soft drink, and a ballgame without a hotdog and a drink seems downright un-American. Every holiday has its own food traditions, each in satiety, from Valentine's candy to Thanksgiving's turkey and trimmings.
In a society where obesity constitutes a major public health crisis, and automobiles are designed with more cupholders than seats, we expect the slightest hunger or thirst to be assuaged immediately.
In the Palestine of Jesus' day, though, those basic biological urges had a more profound meaning. Drought could mean parched crops and starvation or the disappearance of wells that once furnished water abundantly. Even travel - a mundane activity today, whose worst threat is usually nothing more than airport delays - in the First Century was to risk not only robbery but, if the wrong road were taken, an agonizing death of dehydration.
People were aware - always - of the necessity of food and drink and how easily they could be lost.
We think that's probably the approach Jesus had in mind when he spoke of hungering and thirsting after righteousness. He probably was bestowing goodness on those who are always aware of the absolute necessity of righteousness in themselves and in society, and the dire consequences of its absence.
Like travelers in the desert, those who hunger and thirst after righteousness know just how easy it is to take the wrong road. Metaphorically, the wrong road leads toward temptation, away from good influences and those peers and leaders who will hold us accountable, with disastrous results. Wise travelers seek to stay on well-marked paths with known places to refresh and restore their souls.
The same is true for societies. Nations led by wisdom will seek many facets of righteousness - enacting and enforcing laws and societal structures that provide recourse against oppression, that set a stage for prosperity, that provide help for those who cannot help themselves. National righteousness also seeks to distinguish between meaningful standards of behavior whose loss would wreak devastation and those traditions that turn out to be mere preferences and without great importance.
Such nations seek to learn from history and from contemporary failures just how easily and disastrously national righteousness can be lost.
Those who hunger and thirst for righteousness realize their lack, their need, and their whole lives are about the pursuit of its fulfillment. Christians take great comfort in Jesus' promise that such desire will indeed be assuaged.