We are beset with difficulties; beginning with a sound exegesis and a correct hermeneutic we then desire an absence of personal bile and vendetta, and an absence of political predilection, we seek a "just" declaration. We are confronted at the onset with a suspicion from those who hear that the message delivered has a political agenda, and in some traditions we are bound with our confession about not interfering in the affairs of the magistrate.
So how do we not neglect the "weightier matters of the law, like justice and mercy" (Matthew 23:23) without sometimes speaking to the State? How do we do it without picking sides in political arguments or campaigns? How do we do it without offending the very members who pay our salaries? Maybe it would be better to ask, "how can we not do it without offending God?"
Evangelicals tend to preach about moral issues, and liberals tend to preach about justice issues, and both can miss the Gospel when moralizing about any subject. Since the 1970s Evangelicals have become more and more outspoken about public morality issues, especially that of abortion. Abortion is both a moral and justice issue, as it turns out most moral/justice issues are when it comes to behaviors that affect another person beside oneself. That is of course where the rub is, concerning the person-hood of an unborn child.
So many of our issues in America are based on an individual's or a group's view of freedom. A freedom without boundaries invariably leads to invasion of another's freedom. It is sometimes easy to see when a person seeking pleasure without restraint might interfere with the safety or dignity of another person. The law says if you take pleasure in seeing others suffer by hitting, beating, stabbing, or shooting them you are in violation of the law. If you take sexual pleasure in raping or molesting them, you are in violation of the law. There are few who would object to that, even though some in agreement would still be tempted at times to do such things. We consistently draw boundaries against an individuals freedom in order to protect others. An adult individual may wish to have sex with a child but his desire is not allowed, not simply because society feels it is immoral, but it is unjust for one with power to take something from someone without it.
The same conservatives who would vigorously agree with that restraint of individual freedom may not agree that it is right to draw a boundary against someone taking advantage of another economically. The idea that having money gives you power and poverty doesn't means that the poor are easy targets for those who wish to take the little that they have. One present danger is that ideology often leads Christians to excuse injustice in the name of other things, such as free enterprise or even government assistance to the poor. Both have been culprits in grinding the poor into the dust in this country. Free enterprise without restraint says that I can loan a poor person money (who absolutely needs it) and build a system in which they can never default by enlarging that initial loan through late or missed payment penalties and upping the interest rates for late or missed payments. This puts a person who can least afford it into a seemingly never ending spiral of larger and longer term payments. The loaner can act as it they are noble, providing a service that others won't, while deliberately planning to use the poverty of an individual to dig them deeper into a hole. This is followed up by lobbying the legislature to make declaring bankruptcy harder if not impossible.
The ideology of activist government in seeking to provide welfare without tools to re-capitalize the poor creates a system of character destroying dependency. Sustaining people in poverty without building the stairs for them to climb out of it is a maze without an exit. Ideology then defends such systems in the name of compassion and attempts to resist the accusation of injustice.
We are speaking of preaching here, and specifically about preaching justice. Maybe we can give some helpful ideas, but all should be approached with Biblical discernment.
Justice is what is righteous and equitable in relationship to others. It begins with a concept of treating others fairly, and as you would want to be treated. The Scriptures begin this kind of idea with the Sabbath, commanding that even those who work for us also have time to rest. The Scriptures make a big deal of fair measurements, of weights and scales being the same for all. The Scriptures demand that the powerful, the wealthy, and those in government especially are careful to guard the rights of the poor. Since they cannot defend themselves it is necessary for those in power to do so, while those not in authority should be ready to speak up for those who cannot speak for themselves to authority. Justice means noticing and defending, and not being apathetic when others are mistreated, enslaved, tortured, abused, or slaughtered.
Biblical justice doesn't give anyone a pass, if something (bad/unjust) is not happening to you but it is happening to someone else, and you do nothing about it, then the Bible holds you accountable. In this way God demands that we be community, and not simply individuals who act as if other people's problems don't apply to us.
Biblical justice doesn't mean the poor have more rights, or get off in court when they have sinned just because they are poor, it means their rights must be protected. This is an emphasis because they have no defender naturally. Supernaturally God declares himself to be their protector. This is Biblical revelation, God's justice cutting directly against the law of natural selection. Real justice fighting predatory practice.
Preaching from a Reformed theological perspective means that we honor those in politics and government, and at least imagine it is possible to serve in that sphere in such a way as to glorify God. Those who serve in political parties, who get elected, who are appointed must still keep their wits about them as they weigh political platforms, ideologies, and expediency against the Word of God. No Christian is exempt from obeying God in order to pursue political agendas. This includes failing to honor those in authority over us, or to pray for them. Political rhetoric which slanders, lies, or dishonors public officials is sinful. I would say here that listening to other do so without taking exception might also be sinful. Telling the truth is mandated, otherwise in the name of crusading for justice we become unjust, and wicked.
It is easy to obey the Scriptural commands about honoring those in authority when we agree with them, but that is little obedience and costs us nothing. What happens when you have to honor Caesar, who just fed your congregation to the lions? This applies to preachers who preach against injustice, that we would tell the truth, that we would warn about the coming judgment of God, but that we would also demonstrate that we love our enemies and seek not only their repentance but God's mercy for them.
Justice must be preached with some sense of disengagement from personal or political ambition. If it is right it is right, if it is wrong it is wrong. Our American tradition binds preachers not to push candidates or parties, but our American tradition also calls us to great moral/justice preaching. Our people need more Biblical clarity not less. They will always need more faith, more holiness, more knowledge of theology, but if a preacher doesn't think the Scriptures speak to current issues then he must be functionally illiterate, or else he is a blind ignoramus in matters of life.
We must preach justice, and teach its concepts to our people, without neglecting the Gospel, without neglecting the message and ministry of reconciliation. We must preach it boldly, no matter what opposition might arise to us on its account, but we must also preach it with humility and without grinding an ax of personal bitterness. We live in a context of avoidance of social, political, or justice issues in the church while in the context of strident rhetoric about them everywhere else. Our people need more exposure to the prophets, and our preachers need more courage, period.