It is natural for the enemy in the boat to laugh at the knife and cherish the feathers. What does this sentence mean?

This sentence comes from Yuewei Caotang Notes, which is about divination. A scholar went to the exam for a sign and got this sign. Then after the exam, he found that this sign had something to do with the exam questions. This sentence you asked is the content of the sign.

See two grasses in the dark,

The enemy on the ship laughed at the knife,

There is nothing wrong with the fence,

A natural preference for feathers.

The specious words written on the lottery are just to make the lottery draw far-fetched. In fact, you can't see it beforehand, and nonsense can always find a relationship afterwards.

The literal translation of these four sentences should be:

1. I will blame you when I see you in the underworld.

People in the same boat are enemies, hiding a knife in the smile.

The fence has been broken and there is nothing in the house.

It is human nature to cherish and protect yourself.

You can see at a glance that rambling has no practical significance.