My mother was hungry most of her life. She cooked daily for us, but rarely sat down to eat. Unable to stomach the food she'd prepared for the rest of us, she ate her own meals at odd hours, nourishing herself on a strange combination of the ordinary and the exotic. One day she might eat a baked bean sandwich smothered in ketchup; the next, broiled lobster.

Mother blamed her eating habits on a childhood of poverty. Born six years before the Great Depression, her earliest memories were of hunger. Her family was so poor they often went days without eating. When there was food, it was never enough. Sometimes all they had to share between them was a can of beans.

Mother looked hungry. As thin as a wraith much of her life, weighing an almost skeletal 90 pounds, her erratic diet eventually consumed her, shredding her bowels and leaving her emaciated. Unable to keep down food, she died in a hospital bed connected to tubes that provided nutrients for her weakened shell of a body.

My father, on the other hand, died of thirst. A large man with a hearty appetite, his experience was the polar opposite of my mother's. He was raised in comfort. The son of a medical doctor, he observed the poverty of the Great Depression from a distance, never worrying about his next meal.

He started drinking in his teens, I suspect. By the time he reached adulthood, he was a full-fledged alcoholic. He couldn't start the day without a shot of liquid napalm, which he purchased by the half gallon. Like my mother's strange hunger, his thirst for alcohol was the end of him. He spent the last days of his life waiting to have his dry lips moistened with a damp swab, unable to drink water because of his alcohol-ravaged kidneys.

Their experiences are not lost on me when I read Jesus' blessing in Matthew 5:6. Blessed are those who hunger? Hunger and thirst signal need. They are symptoms of emptiness and unfulfilled desire. How can they be a source of blessing?

The fact that Jesus says he is talking about hunger and thirst for righteousness clarifies little. He seems to have put the emphasis in the wrong place. Why not, "Blessed are the righteous?" Hunger implies a lack of righteousness. Jesus' proposal is so radical, it turns our notions of God and righteousness and blessing on their heads. He blesses what most of us would curse.

According to Jesus, when we draw near to the kingdom, it is better to come empty than full. We are tempted to think that righteousness is the condition we must be in to be blessed. Jesus says the opposite. Righteousness is the blessing; hunger is the precondition.

Eating and drinking play significant roles in Old Testament worship. Indeed, the shedding of blood was at the heart of the Mosaic covenant. As the writer of Hebrews notes: "The law requires that nearly everything be cleansed with blood, and without the shedding of blood there is no forgiveness" (Heb. 9:22). Where there was shed blood, there was also food. Priest and worshiper alike celebrated God's provision of righteousness with a meal.

Old Testament worship made special note of the prodigal nature of our appetites. The Law of Moses, with its long list of clean and unclean foods, seems obsessively concerned with diet. Some have interpreted these regulations primarily as a regimen for healthy eating, but I think the message is more serious. The list reminds us that we are addicted to an unwholesome diet. Righteousness is not our natural food. As a result, we are being consumed by our appetites. Like our first parents, whose hunger for forbidden fruit in the Garden of Eden led to the fall of our race, we too long for food which seems good, pleasing, and desirable, but which will destroy us in the end. Even worse, our efforts to sate our hunger and slake our thirst ruin our taste for a better diet.

In Jesus' beatitude, we hear an echo of the prophet's complaint: "Why spend money on what is not bread, and your labor on what does not satisfy? Listen, listen to me, and eat what is good, and your soul will delight in the richest of fare" (Isa. 55:2).

Yet our tastes have been captivated by other delicacies. We log onto the internet and feast our eyes on things which sicken the soul. We turn on our televisions and get drunk on the wine of violence. We fill our stomachs with the bread of idleness and cast our leavings to the poor, trying in vain to suppress the gnawing desires that eat at our hearts.

So God takes steps to help us get over our taste for food that cannot satisfy. To our discomfort, the main tool he uses is hunger.

During Israel's years in the wilderness, God let them feel this hunger painfully. "He humbled you," Moses explains in Deuteronomy 8:3, "causing you to hunger and then feeding you with manna, which neither you nor your fathers had known, to teach you that man does not live on bread alone but on every word that comes from the mouth of the Lord."

It's no wonder that Christ quoted Deuteronomy 8:3 when Satan taunted him in the wilderness. Ours is a hunger no earthly bread can satisfy. We don't want to spoil our appetite.

It's also no wonder that Christ sacramentalized our need for food and drink in the Lord's Supper, using hunger and thirst to point us to better fare. "Whoever eats my flesh and drinks my blood remains in me," Jesus told a hungry crowd early in his ministry, "and I in him" (John 6:56). In our effort to distance ourselves from the Roman Catholic doctrine of transubstantiation, we Protestants have understood these claims primarily in negative terms. We spend so much energy emphasizing what Jesus does not mean that his words fail to whet our appetite. But the positive symbolism of the Lord's Supper is powerful: Christ alone can satisfy. Christ alone can sustain. All that we hunger for must be found in him.

Why is blessedness associated with hunger? Because those who bring their hunger to Christ will be filled with his righteousness. Thus, righteousness must be a gift before it can become a practice. The promise of righteousness is offered to those who are empty. It belongs to those who are aware of their lack.

We cannot labor for Christ's righteousness. Even if we wanted to work for it, we could not expend enough effort to obtain it. If we wanted to buy it, we could not offer enough money. We can't get it by loan. The only way to obtain righteousness is to receive it.

The language of filling in Christ's beatitude underscores another important aspect of the blessing. Righteousness works from the inside out. We usually go about it the other way around; we try to work on it from the outside in, as if it were a matter of externals. If we worship in the right building, perform the right rituals, wear the right clothes, and are seen with the right people, we are righteous. If we read our Bibles and pray in the morning, give a tithe of our earnings on Sunday, control our tempers and restrain our passions the rest of the week, we are righteous.

But if we listen to Jesus, we begin to understand why he attracted the sort of people who came to listen to his preaching: hookers and thieves, trailer trash and lowlifes, people who dwelled on the outskirts, in places where decent citizens refused to travel. If we dare to hear Jesus rightly, we understand why respectable, law-abiding people such as ourselves wanted to silence him. It is because this word of Jesus has the power to strip us of all we think we've achieved. This beatitude robs us of what we thought we had acquired and leaves us naked, destitute, and empty. If we are to have righteousness as Jesus defines it, we must receive it like beggars, letting it transform us from the inside.

Above all, Jesus' promise in this beatitude shows us that true righteousness leaves us craving more. We tend to think of righteousness as a standard. Like the little boy whose progress in growth has been marked inch by inch on the kitchen wall and compared to his father's height, we hope that we, too, will measure up someday. Yet there is no limit to God's righteousness, as if we could accumulate and eventually exhaust it. God has an infinite capacity for righteousness, and so do we. This is the secret to savoring the blessed hunger Jesus describes. Natural hunger is all about emptiness. The hunger Jesus blesses is about never being filled.

Such is our lot—and our blessing. As worshipers of an infinite God, we are always longing, always filled.

John Koessler is chair of pastoral studies at Moody Bible Institute and author of A Stranger in the House of God (Zondervan).

Recent Reflections columns on the beatitudes include Blessed Are Those Who Mourn, Poor in Spirit, and Blessed Are the Meek.

John Koessler also wrote "Come, Lord Jesus—But Not Too Soon" and "Why I Return To The Pews" for Christianity Today.

An audio blog and information about his books and articles are available on Koessler's website.