Forrest Hamer's poem "Lesson" features literary devices like metaphor, personification, and vivid imagery to enhance its message.

In the poem's second stanza, the speaker describes the dark as "hanging from the trees" the way moss does. This is a very vivid image as well as a metaphor. There is something menacing about the dark, something suffocating and oppressive. The speaker and his family cannot escape the dark.

The speaker also personifies the dark. It moans against the windows. Again, there is a threat here. The speaker stays awake listening to the noises, and his father is awake, too. The speaker, who is a child, is usually afraid of monsters, but he is learning that he has other things to be scared of, too.

There is a loud fury inside the speaker as he thinks of what his father has to do. He is taking his family to safety, and then he will go to Vietnam. This fury is a metaphor for all the tangled emotions the speaker feels about this. He wants his father to stay with him, but he is learning that his father may not always be able to protect him. This is a hard lesson indeed.