Think about the basic human emotions we get to preach on: joy, sadness, comfort, anger, and serenity. Now think about the prophets—which emotion most often characterizes them?

A few examples:

"Hear this word, you cows of Bashan on Mount Samaria, you women who oppress the poor and crush the needy and say to your husbands, 'Bring us some drinks'" (Amos 4:1).

"Stop bringing meaningless offerings! Your incense is detestable to me. I cannot bear your evil assemblies" (Isaiah 1:13).

"Should you not know justice, you who hate good and love evil; who tear the skin from my people and the flesh from their bones; who eat my people's flesh, strip off their skin, break their bones in pieces, chop them up like meat for the pan?" (Micah 3:1b-3).

Don't the prophets strike you as kind of cranky? Not only do they use angry words, prophets resort to shock tactics that often look downright bizarre:

—Hosea marries a prostitute to show how unfaithful the people have become;

—Ezekiel eats food cooked over excrement to show people how defiled they've become,

—Jeremiah digs up a filthy, buried, unwashed undergarment to show people how repulsive their behavior was.

The prophets are filled with this stuff. No wonder those of us who preach often avoid them. Our listeners don't always like it. We don't like it. (Does anyone really want to encourage such prophet-like behavior in their congregation?)

We like happy books. In most of our churches, it is easier to preach comfort rather than judgment, mercy rather than justice, because by the standards of God's justice, who can ever measure up?

On the other hand, these passages are in the Bible. In fact, the prophets directly account for 250 of the 1,189 chapters in the Bible. Can you really be a biblical preacher and not address what the prophets have to say?

Why we must preach on justice

More than that, there is a reason why we need to preach on justice. There is a reason for the anger of the prophets, and why we need to submit ourselves to the discipline of regularly sitting under and preaching their words.

Imagine you're listening to someone sing. They are singing off-key, badly off-key, and they're singing loud. If you are musically insensitive—have a tin ear—it doesn't bother you much. If you are musically insensitive and the singer is your grandchild, it may actually make you very pleased.

But if you have perfect pitch—it's a different story. You know what the song could be, should be. You know how far it's off. You look at tin-ear grandma and wonder, How can she stand to listen to this?

This is painful. You're in agony.

We read the prophets and think: What's the big deal? What are they getting all heated up about?

To us, the world is not so bad. Most of us are pretty happy. Things are going okay—at least for me.

I know there's violence in the world. It's regrettable, but as long as it doesn't touch my life, I would prefer not to think much about it. Certainly that's not connected to my anger, self-centeredness, lack of love.

Cheating goes on every day in business. Somebody shades the truth a little for profit—that's just the way things are.

Some 8,000 children are born with or infected with HIV every day in sub-Saharan Africa, and it's now the leading cause of death.

A few miles away from my church, from any church, children are born in poverty, living in ghettos or slums; they will grow up without access to decent education, housing.

But they're not my children. Maybe their parents did something to deserve it. So what if in ancient Israel the poor often got the shaft? Where is it any different? Why go off the deep end?

The prophets act like the world is falling apart.

What's the big deal?

The prophets have been given the crushing burden of looking at our world and seeing what God sees: rich people trying to get richer and looking the other way while poor people die. And thinking God is really pretty pleased with their lives. And that the world is going pretty well.

We tend to avoid preaching about justice because we don't really want to know the truth about what sin has done to our world and to us. Because that would make us uncomfortable.

As Micah 2:11 put it: "If a liar and deceiver comes and says: 'I will prophesy for you plenty of wine and beer,' he would be just the prophet for this people."

We prefer preaching that tastes great and is less filling.

To paraphrase the great scholar Abraham Heschel, "The shallowness of our moral comprehension, the incapacity to sense the depth of misery caused by our own failures, is a simple fact of fallen humanity which no explanation can cover up."

Events that horrified the prophets go on every day in our world, but we just get used to it—like you get used to wearing your watch. After a while—we don't notice any more.

The prophets noticed. The prophets never got desensitized to sin. Injustice is sin. Justice is central to shalom. We omit justice from our preaching at peril of our calling, and of our congregation's health and ability to see the reality around them.

Why preaching about justice is hard

But … there are a host of challenges in preaching about justice.

Our society has become so politicized that people often hear words like justice or life or the poor or compassion as code words for a partisan political allegiance in one direction or another.

Preaching about justice can drift quickly into self-righteous moralism. Many people claim the spiritual gift of prophesy when what they really have are anger management issues. There is a thin line sometimes between being a prophet and being a jerk.

Generational issues can come into play. Older members of a congregation may have been part of a denomination that drifted away from orthodox belief and replaced it with a social agenda. They may have been shaped by this experience, much as children of the Depression are forever marked in their financial lives. So talk about "justice" may bring alarm to some members, where absence of such talk may produce alarm in others.

Preaching about justice can also play into a dangerous trend in our day where ideological correctness replaces character development. People may mistake being on the "right side" of social issues with having a transformed mind and heart.

Concern for justice must also be rooted in Jesus and tied to Scripture. Historian Mark Noll noted that one shortcoming of the abolition movement was a failure to do the exegetical and theological work needed to base abolitionism in the authority of Scripture. As a result, reform movements after the Civil War (from women's rights to temperance to child labor) became increasingly detached from Scripture, and they became increasingly separated from the concerns of the church.

So how do we preach about justice in ways that can unite, and inspire, and form Christ more deeply in our congregations?

Justice is not partisan politics

Sociologist James Hunter has written a tour-de-force critique of evangelicalism and culture called To Change the World. He argues that in our society the public square has become so politicized that people assume all public expressions of art or literature or religion can be placed on a political spectrum from left to right. This means that—unless we preach with great skill—our listeners will assume that words like justice or poverty or sexuality or life or righteous are really code words for a partisan political position.

We will have to explain that the values embedded in the Bible do not necessarily have a straight-line translation into legislation. For instance, all followers of Jesus are obligated to be concerned for the poor. But that does not mean that they should all be committed to passing a higher minimum wage law. Very bright economists disagree about whether such legislation actually results in helping the poor. As preachers, we do not further the cause of the authority of Scripture when we pretend to be experts over fields we have not mastered.

Walt Gerber was for over 25 years senior pastor of the church where I now serve, and he had a wonderful phrase in this regard: "This is a Jesus church." Anytime someone wanted to push for a political agenda, Walt would remind the congregation that we desire to be a place where anybody—regardless of political affiliation—could come to learn about God. "This is a Jesus church."

A call to action is not asking a favor

Our church recently did a six-week series on justice issues (poverty, pandemics, creation care, etc.). I started by noting a Nicholas Kristof New York Times column describing two people:

"Richard is an ambitious 36-year-old white commodities trader. He lives in Hawaii. He is healthy, handsome, lives alone in a house with a pool, has dated a series of gorgeous women. His job is stressful, but he spent Christmas in Tahiti. He is free to indulge in such passions as reading, marathon running, and writing poetry, and is currently composing an elegy about the Haiti earthquake.

"Lorna is a 64-year-old black woman. She lives in Minot, North Dakota. She is overweight and unattractive. Lorna is on regular dialysis, but that doesn't impede her social life or babysitting her grandchildren. A retired school assistant, she is close to her 67-year-old husband and is respected in her church for directing music ministries and leading the semi-annual blood drive. Lorna believes in tithing, and in the last few days has organized a church drive to raise $10,000 for Haiti."

The first question was: which of these two would our society put forward as an example of the good life—which one would companies want to use as a spokesperson to say "if you buy our product you can have their life"—Richard or Lorna?

The next question was: which one is more likely to be happy? Here's where the research gets interesting. Gender has no impact on happiness. Climate and weather have no impact on happiness—there are happy people in North Dakota. They may not be real bright, but they're happy.

Beautiful people are not happier than ugly people.

Younger people are actually a bit less happy than older people.

Turns out that happiness is tied to volunteering, to donating, to giving blood, to serving others. People with vital faith in God tend to be more joyful than those without.

Dr. Stephen Post heads an institute that has funded high-level research on human compassion at over 44 major universities.

The remarkable bottom line of the science of love is that giving protects overall health twice as much as aspirin protects against heart disease. He says the benefits of compassion just to your physical health alone are so strong that if compassion wasn't free, pharmaceutical companies would herald the discovery of a stupendous new drug called "Give Back" instead of Prozac.

Lorna will most likely live longer, be happier, have more friends, experience more purpose, nurse fewer regrets. But that's not what matters most.

When we ask people to involve themselves in justice issues, we are not adding a burden on to their busy lives, or asking them to do the church a favor. Ultimately, what matters most is a third question: Which person is more like God—Richard or Lorna?

God himself has a certain kind of character. In that message, we simply ended up walking through the character of God, and I asked people to give God a 1-10 rating on:

Compassion

Commitment to justice

Concern for the poor

Generosity

Love

By the time we had looked through Scripture on these issues, all of us were ready to say "uncle." But our concern for justice must start with and flow out of the character of God rather than any fashionable, merely human agenda.

Make justice concrete

In some churches, where many attenders are well off, we may have to remind ourselves of how badly injustice stings. Sometimes it happens in mundane and funny ways. Dave Hagler served as an umpire in a softball league in Boulder, Colorado. One winter he was driving too fast in the snow, and a policeman issued him a ticket. He tried to talk the officer out of it, but the officer told him if he didn't like it he could go to court.

The first game of the season that Hagler umpired, the first batter to come to the plate was the police officer. They each recognized each other. The officer asked, "How did the thing with the ticket go?"

Hagler replied: "You better swing at everything."

We hate it when someone treats us unfairly—at work, in family. The call of Jesus is to get as energized about someone else's being the victim of injustice as you are when it's you. In particular, be concerned about injustice to those you might be inclined to overlook.

This is another concrete story, from a woman quoted in Miraslov Volf's wonderful book Exclusion and Embrace:

On the cross we see most clearly god's hatred of injustice. an empty tomb proclaims most loudly justice's final victory.

"I am a Muslim, and I am 35 years old. To my second son, I gave the name Jihad so he would not forget the testament of his mother—revenge. The first time I put my baby at my breast I told him, 'May this milk choke you if you forget.' So be it. The Serbs taught me to hate. [She describes her work as a teacher and how the very people she taught and cared for became her enemies.] My student Zoran, the only son of my neighbor, urinated into my mouth. As the bearded hooligans standing around laughed, he told me: 'You are good for nothing else, you stinking Muslim woman.'"

Jesus often surprised his followers by being concerned for those whom others were inclined to overlook.

Provide an opportunity for action

At our church, we began an experiment five years ago where we shut down our worship services one weekend a year and worshipped God by serving folks all around the San Francisco Bay area. For us, there was something about not holding services for a weekend that got people's attention, and we have close to as many people serving on Compassion Weekend as we would have attending on a normal weekend. Interestingly, an increasing percentage of those folks are from outside our church, and often are searching in their own spiritual lives.

On another weekend, one of our pastors, Kevin Kim, was preaching about justice, and invited people to take out their cell phones during the sermon (a practice I don't normally encourage) and text a donation to a ministry that fights sex trafficking. The only challenge was an unexpected need to do an impromptu tutorial on texting donations. But people loved being able to take immediate action.

When preaching justice, one experience can be worth a thousand sermons.

Justice points to Jesus

Maybe the most important message for me to remember in preaching is that justice matters because of Jesus. His kingdom is a place where justice prevails, so I cannot love him without loving the justice he prizes.

So we are to remind people that it is in Jesus that justice prevails. The cross was the scene of the most monstrous injustice in history, where the one truly innocent person in history was visited with the sum total of human sin.

It is on a cross we see most clearly God's hatred of injustice. It is an empty tomb that proclaims most loudly justice's final victory.

And so Jesus' people are called to form a community where shalom prevails. I love the translation Eugene Peterson gives in Acts 2 of the way the world looked on the early church "and in general, liked what they saw" (Acts 2:47, The Message).

May it happen again.

John Ortberg is pastor of Menlo Park Presbyterian Church in Menlo Park, California.