Proverbs 22:3 Know when to stop

The prudent see danger and take refuge, but the simple keep going and pay the penalty.

A very practical proverb like this one has more than one application for the preacher. It is undoubtedly good to preach series of sermons from books of the Bible but if you find your series wearying the congregation, better to leave it and move on to something else. One reason Spurgeon gave for avoiding lengthy series was his boyhood experience with a preacher's interminable series on Hebrews.

He recalled

I have a very lively, or rather a deadly, recollection of a certain series of discourses on the Hebrews, which made a deep impression on my mind of the most undesirable kind. I wished frequently that the Hebrews had kept the Epistle to themselves, for it sadly bored one poor Gentile lad. By the time the seventh or eighth discourse had been delivered, only the very good people could stand it: these, of course, declared that they never heard more valuable expositions, but to those of a more carnal judgement it appeared that each sermon increased in dullness. Paul, in that Epistle, exhorts us to suffer the word of exhortation, and we did so. I also recollect hearing in my younger days long passages out of Daniel, which might have been exceedingly instructive to me if I had obtained the remotest conception of what they meant.

I heard of a man who never announced a series but would always say he was preaching from Chapter 1 and see how it went.

The same danger lurks in the individual sermon. Martin Luther warns “Some plague the people with too long sermons; for the faculty of listening is a tender thing, and soon becomes weary and satiated.” Prayers are another area where the proverb could apply. Spurgeon again complained about people who "pray us into a good frame of mind and heart, and then, by their long prayer, pray us out of it again". He recalls John MacDonald saying “When I am in a bad frame of mind I always pray short prayers, because my prayer will not be of any use, and when I am in a good frame of mind and heart, I pray short prayers, because if other people are in a good frame too, I might, if I kept on longer, pray them into a bad frame.”
An anecdote is told of D L Moody that in one of his meetings in the East End in 1885 someone was leading in prayer but went on too long. After a while, Moody stood and said, "Let us sing a hymn while our brother finishes his prayer." The source of the story is Dr. W. T. Grenfell. In his autobiography, A Labrador Doctor he tells how the prayer had so wearied him he was about to leave. Moody's prompt action kept Grenfell there and he was converted and went on to be a great medical missionary. 

Proverbs 23:9 Ignore fools

Do not speak to fools, for they will scorn your prudent words

When we preach we want to cast the net as widely as is possible. However, we need to recognise that there are some whom it is impossible to reach through the ordinary preaching of the Word. Fools, that is those who are morally deficient and without faith and here wilfully and persistently deaf to the gospel, cannot be reached by this means. Such people will scorn your prudent words. They will not listen. This is why Jesus (Matthew 7:6) warned his disciples not to throw pigs to pearls or what is sacred to dogs. Indeed, he suggests that it may be worse than the proverb intimates - they may turn on you and harm you. 1 Corinthians 1:18 says that the message of the cross is foolishness to those who are perishing and so although God himself can break through preaching to fools cannot of itself. From time to time people will turn up at church who have no intention of doing anything but scorning the Word. They will not be persuaded.

Proverbs 24:26 Be honest

An honest answer is like a kiss on the lips

Honesty is the loving way, the right thing to do. Paul calls it speaking the truth in love. If a preacher fails here, he fails entirely. We must tell it like it is. That does not mean being insensitive but it does mean preaching sin and death and hell in biblical proportion. It may not be the way to universal popularity but it is the loving way. Horatius Bonar quotes Rowland Hill. in his Words to winners of souls, "Rash preaching disgusts; timid preaching leaves poor souls fast asleep; bold preaching is the only preaching that is owned of God."

Philip Jensen preaching on the need for boldness has said

We are still in spiritual need of prayer, to preach the gospel fearlessly with boldness. The same fears of shame and persecution, of put-down and ridicule, are there in me and in you as they were in the apostle in chains. So we need to pray for one another - and I need you to pray for me - that we may speak the mystery of the gospel fearlessly as we ought.

The same attitude should be in all preachers. 

Proverbs 24:11, 12 Rescue; hold back

Rescue those being led away to death; hold back those staggering toward slaughter. If you say, “But we knew nothing about this,” does not he who weighs the heart perceive it? Does not he who guards your life know it? Will he not repay everyone according to what they have done?

If you are a gospel preacher then you are something like a lifeguard rescuing people from the sea, a firefighter saving them from a burning building or a secret serviceman charged with protecting the president who is under fire. You are involved in a vital rescue mission. The people before you, unless they are converted, are those being led away to death the death of hell. They must be rescued. Your work is to hold back those staggering toward slaughter. Of course, for the preacher to say “But we knew nothing about this,” and pretend ignorance will not do. God who weighs the heart will perceive it if you make such a false claim. The one who guards your life, he knows the truth. The fact is that God will repay everyone according to what they have done and so the work of rescue, the work of holding back is vital. Those who preach faithfully want to turn sinners away from sin and see them saved. Peter Jeffery has written that "The task of the gospel preacher is the salvation of souls, and he should be satisfied with nothing less." He is right. We must be desperate to see sinners saved.

Proverbs 24:6 Take advice

Surely you need guidance to wage war, and victory is won through many advisors.

Reformed pastor Tom Ascol has written that "preaching is spiritual warfare and it is a rare Lord’s Day that I do not go home painfully aware of the attacks of our enemy that have come before, during and after my efforts in preaching. I suspect that most preachers know something of what I am talking about."
When a man preaches God's Word he is going to war, as it were. He is storming the strongholds of Satan, seeking to win people to Christ. If he is to be successful in this war, if he is to win any battles tat all, hen he needs to get all the help he can. First, you need guidance on waging war. Read books on how to preach, listen to a variety of preachers and see how they approach the task, ask questions, study the subject. It will all help you to wage war. If you want to be victorious, it is useful to get the help of many advisors. Get the commentaries out, consult the systematic theologies and other Christian books. Simply looking to ourselves is foolish indeed. Rather, under God, we must make the best use we can of all the resources available to us.

Proverbs 26:6 Fools need not apply

Sending a message by the hands of a fool is like cutting off one’s feet or drinking poison.

It is important that a preacher is not a fool, that is a moral reprobate, one who is unable to do what he is asked. Putting a fool in the pulpit to preach is like cutting off your feet so that you cannot walk or drinking poison so that you will no longer live. A preacher is meant to bring a message from God. If he is a fool he will be unable to do so. Preachers need, therefore, to be converted men who are properly trained and who thoroughly prepare to preach.

Considering the call to the ministry R L Dabney gives balance to this point by writing that while on one hand

we freely assent that Christ has no use for fools in the pulpit. The impotent, beggarly, confused understanding should not undertake to teach other minds. And the very noblest capacities are desirable, and will find ample scope in this glorious work.

Nevertheless some young men wrongly

excuse themselves by profess­ing a doubt whether they have natural talents adequate to so responsible a work as the ministry

(Dabney that's he fears that "in many cases, if their friends were to concur candidly in this doubt, their vexation would betray the insincerity of the pretended hu­mility"!).

He goes on to say that

nothing more than respectable good sense and justness of mind is requisite to secure such usefulness in the ministry as should decide any pious heart, if that mind is used to the best advantage. Let the heart be warmed and en­nobled with Christian love, the good common mind will be ex­panded and invigorated, and a conscientious diligence will give it an indefinite and constant improvement. Love and labour will make the small mind great.

He refers to a then recent memoir of Dr. Daniel Baker as containing an instructive testimony on the point. "His energy and success in the gospel" Dabney says

led some to remark how emi­nent he might have been in worldly pursuits; what a millionaire, if a merchant; how eloquent, if a lawyer; how popular, if a statesman! But his biographer, who is his own son, says: “No; it was his religion that was his strength; grace alone made him great.” Blessed be God, the church has often found that plain talents, faithfully improved for God, by love and zeal, have ac­complished the largest good.

Dabney concludes

Let the young Christian, then, judge his own qualification by these truths. It is clear that, in the general, the church must always expect to find her ministers precisely among those who honestly appraise their talents mod­erately. For who would like to see the young Christian come forward and say “that he felt called to preach because he con­sidered himself so smart!”

Proverbs 26:4, 5 Answering fools

Do not answer a fool according to his folly, or you yourself will be just like him. Answer a fool according to his folly, or he will be wise in his own eyes.

This famous pair of proverbs state opposite approaches to dealing with fools. This, of course, is no contradiction as these are proverbs and where such material may appear to contradict the key is in how the proverbs are applied. In this very chapter we are told (verse 7) Like the useless legs of one who is lame is a proverb in the mouth of a fool and (verse 9)  Like a thornbush in a drunkard’s hand is a proverb in the mouth of a fool. The trick with these two proverbs then is knowing when to employ which. There are times when a preacher ought to simply ignore what unbelievers say and other times when he ought to tackle unbelief head on and show where it is deficient. Indeed from time to time the demand will vary. Take atheism for example. A preacher who peppers his sermons always with references to atheism and how wrong it is will be in danger of undermining his own argument by giving the impression that there is some strength to the atheist argument. Of course, if a preacher never touches on such a subject he may also give the impression that he has no answers.