The whole Bible is the word of God. All Christians would agree with that, but probably most would say that parts of it are more useful than others. We struggle with those long genealogies, for instance, and we can't always see the point of all those Old Testament laws – though we believe they have a point.

Some Church traditions lay down programmes of preaching for their ministers through a weekly 'lectionary' that gives them the passage for the week. It takes them through a good chunk of the Bible, usually over a three or four-year period. Others stress the value of 'consecutive exposition', where a whole book of the Bible is expounded verse by verse or chapter by chapter. That way, the argument runs, you can't miss anything out even if you wanted to.

But are there bits of the Bible that we just don't hear preached on at all? Here are 10 Old Testament passages your pastor has almost certainly avoided, either because they're too gory, too shocking or just too hard to make anything of.

1. Genesis 19: 30-37

It's the story of how Lot was made drunk by his two daughters so they could have sex with him and bear children (who turned out to be the ancestors of Israel's deadly enemies, the Ammonites and the Moabites). It's all rather sordid and horrible. There are lessons in it about consequences and family dysfunction, but it's not an appealing story.

2. Genesis 30: 25-43

Jacob wants to go his own way from his father-in-law Laban, but needs to build up his resources first. He asks for all the spotted and striped sheep and goats, and Laban agrees. He gets the flocks to mate in front of fresh-cut branches in which he's cut stripes, and their offspring all turn out to be striped too. It's just one of those stories we struggle to find anything to say about.

3. Numbers 22:21-41

This is about Balaam's donkey. The prophet is asked to curse Israel on behalf of the Moabites, but as he's on his way an angel with a drawn sword standsin front of him, visible to the animal but not to Balaam. Understandably, the creature stops; less understandably, it complains to Balaam when he beats it. There are certainly things to learn from it, but it just seems too weird.

4. Judges 19: 1-30

This is one of the most brutal and terrible stories in the Bible. A man and his concubine stayed in the town of Gibeah overnight. A crowd gathered wanting to have sex with the man; he sends them his concubine instead and they rape her to death. He chops up her body and sends the pieces to the rest of the Israelites so they can see what's been done.

In the end, this turns out to be a story of God's justice. But it's strong meat – too strong for most churches.

5. 1 Samuel 27: 1-12

David is the greatest king and hero of the Old Testament. Before he became king, he spent time with the Philistines, sheltering from Saul. He still raided Philistine territory, though, and to keep the Philistine king from becoming aware of his depredations he killed everyone in the villages he targeted: "He did not leave a man or woman alive" (verse 11); we have to assume he killed the children too. It's a long way from the image of David we like to portray, and very hard to preach on.

6. 2 Kings 2: 23-25

The prophet Elisha appears to have been follicly challenged. He's walking along when some boys make fun of him; two bears come out of a wood and maul them, which seems a bit extreme. What's going on here? Perhaps it's about respect for elders, or perhaps he was tonsured like a monk as a sign of his office. Either way, it's a challenging preach.

7. 2 Kings 6: 1-7

Another Elisha story. One of his band of prophets drops an axe into the river and is upset because it was borrowed. Elisha throws a stick into the water and the axe-head floats to the surface. It's one of several Elisha miracles that just seem odd – a bit too domestic, perhaps. There is a lesson there when you read them all together – his actions are symbolic prayers, acting out what he wants to happen – but on the whole, these stories are ones preachers avoid.

8. Psalm 137: 8-9

These are the verses that speak of God's blessings on the one who "seizes your infants and dashes them against the rocks". And the Psalm starts so well, with that lovely lament for Jerusalem: "By the waters of Babylon we sat down and wept..." The last verses are hardly ever read in public worship; they seem sub-Christian. But they should be: they're a deeply honest acknowledgment of the desire for revenge. Until we acknowledge anger, we can't deal with it.

9. Ezekiel 23: 1-49

A remarkably graphic, no-holds barred allegory of Israel and Judah, characterising them as two adulterous sisters. Some of these verses are Not Safe For Work and would bring blushes to the faces of most congregations.

10. Daniel 6: 24

Who doesn't enjoy the story of Daniel and the Lions' Den? It has a happy ending, with Daniel rescued alive against all the odds. But it's a rare preacher who will go on to talk about how the story actually finishes – his accusers, with their wives and children, torn to pieces and devoured in his place. That's not the version we tell in Sunday school. Sin, though, has consequences – not just for ourselves, but for others.

There are some parts of the Bible we find it really hard to fathom, and so we're likely to leave them alone. But never forget what Mark Twain wrote: "It ain't the parts of the Bible that I can't understand that bother me, it's the parts that I do understand."

Mark Woods is the author of Does the Bible really say that? Challenging our assumptions in the light of Scripture (Lion, £8.99). Follow him on Twitter: @RevMarkWoods