Start with the joke, because the poem does. Calling a gun's threat "an excellent sermon" is the language of someone leaving a church and praising the preacher. Here that approval is turned on the very thing that ends conversation. The title, "Louder than words", clips the old saying that actions speak louder than words. Everything that follows is about what kind of action that is: force, standing in for argument, makes a division plain. Twenty-one words later, the poem has moved from the gun to its effect on the speaker, and the effect is a loss.
The central metaphor is smaller than it first looks. A sermon instructs. It assumes an authority and a congregation that has to sit and listen, and it usually teaches who stands where in the moral order. The gun does all this without a syllable. Its lesson is "the difference between us", and the poem never says who "us" is. We are not told who holds the gun, who faces it, or what separates them. That silence lets readers bring their own divisions, but it also suggests something harsh: the difference only becomes undeniable once one side is armed. There is irony in the poem's own position too. The title promises something louder than words, yet the poem has only words to describe it, so it has to work by understatement rather than volume. "Excellent" is the quietest, driest word in the piece. It admits the lesson was effective and the teaching complete.
The construction is plain. There are two couplets, no rhyme, and no punctuation at all, so the lines run on like speech. The longer, more formal words, "excellent", "sermon", "difference", "between", crowd into the first couplet, which has the measured sound of a pulpit. The second couplet drops into everyday talk and ends on four single syllables: "how not to see". The rhythm slows to fit them. Each word is stressed almost equally, so the line lands like footsteps, and it is hard to read quickly. Sound ties the halves together more quietly. "Gun" and "us" share a short, dull vowel and bracket the first couplet. In the second, "forgot" and "not" echo each other across the line break, so the sound of the negative sits inside the act of forgetting.
The grammar changes with the sense. The first couplet is one confident sentence in which "the gun" is the subject and "made" is a decisive verb. In the second, the subject is "I", and the sentence opens with a hedge: "I am afraid". That phrase works two ways. It is the polite, apologetic phrase of someone admitting a small lapse, like "I'm afraid I've lost my keys". It is also literal fear. The poem lets both meanings sit together, and the mildness of the first makes the second more unsettling. "Forgot", in place of the more usual "forgotten", has an old-fashioned ring, a faint echo of the sermon's register, though the speaker's voice is otherwise casual.
Then comes the final line, which is the hardest to pin down. To "forget how not to see" means losing the ability to be unaware. It could be about memory: the sight of the gun cannot be erased. It could be about knowledge: once the difference between "us" has been shown by force, the speaker cannot go back to behaving as if it did not exist. Or it could be about conscience, since looking away is a kind of innocence, and the speaker has lost the right to it. The poem does not choose. The wording is odd, a double negative that makes ignorance a skill that can be forgotten, and that oddness holds all three readings together. The speaker's only response is a subtraction: the ability to look away has been removed.
The poem is worth reading because it refuses to preach. The gun delivers the sermon, and the speaker merely confesses what it left behind. In a few lines a poem that mocks sermons becomes a small lesson in how violence teaches, and how permanently. We reach the last line having learned the same thing the speaker has, and we cannot unread it.