2 Chronicles 9:25

25 And Solomon had four thousand stalls for horses and chariots, and twelve thousand horsemen; whom he bestowed in the chariot cities, and with the king at Jerusalem.

1 Kings 4:26

26 And Solomon had forty thousand stalls of horses for his chariots, and twelve thousand horsemen.

This is a very famous and oft-repeated alleged contradiction in the Bible. The account in 2 Chronicles says 4,000, the account in 1 Kings says 40,000. Which is it?

Solution

Read carefully. Solomon had 40,000 stalls just for horses. He had 4,000 stalls for horses and chariots.

That equates to each chariot being assigned a team of 10 horses. If one dies, gets injured, or gets tired, they return, restock, and get back out to battle.

Alternatively, we can recognize that if Solomon had 40,000 of something, it's also true that he had 4,000 of that same thing, and one account could simply be being less precise.

Conclusion

Based on the author's perspective, they highlighted different aspects of the army. The author of Chronicles focused on the horses, the author of Kings focused on the chariots. There is no contradiction.