A man sits alone, and the first thing the poem does is turn him into architecture. "Alone, he is a castle keep" doesn't say he lives in a fortress. It says he *is* the innermost tower, the last stronghold where a besieged garrison retreats. "Keep" works twice here, as a noun for a building and as a verb for holding on, holding in, holding back. The opening comma matters too. "Alone, he is…" reads like a condition: it is when no one else is there that the walls go up, or at least when they are most visible.
"Still with fear" follows, and "still" carries two meanings at once. It can mean motionless, which suits a stone tower, and it can mean "even now," which suggests a fear that has been there a long time. The colon promises an explanation. What arrives is a question, though the poem never gives it a question mark: "will love find him / in a lie, saying…" By the end the sentence has only trailed off into an ellipsis. The poem asks and then leaves us waiting.
The title, "Of human bondage," is a phrase many readers will know as the name of a Maugham novel. The poem itself doesn't say whether it means the echo. What the phrase does here is turn on the word "bondage," which has two faces: being imprisoned and being bound to other people. Love is a bond, and so is a wall. The poem's central idea seems to be that the man has fortified himself against one kind of bondage and ended up in another, so that fear is both architect and jailer.
The second half is harder to pin down. "Find him in a lie" could mean catch him out, or it could mean find him living inside a falsehood, perhaps the pretence that the keep is a safe place to be. The word "saying" hangs across the stanza break with no clear speaker. Is it love, the man, or the lie itself? Then comes the claim "that it was the same outside / as with a lock and a state." One reading, which is an inference from the text, is that this is the lie: the shut-in's comfortable excuse that the world beyond the wall is just as locked as he is, so there's no point leaving. The pairing "a lock and a state" is odd. A lock is small and domestic, while a "state" is vast, political, or a condition of mind. Confinement seems to scale up from a single door to a whole way of being, and the poem lets us feel that without explaining it.
The form supports this. The poem is free verse with no rhyme, and "keep" and "fear" refuse to chime, which fits a speaker-less, connection-shy mood. Yet the first line is almost regular, four beats in eight syllables, like a sturdy wall. After that the lines shrink to "still with fear" and then loosen into the longer, wandering final two. The three couplets are like small rooms, each sealed off by white space, and the syntax has to strain over the gaps. Listen also to the *l* sounds running through the poem: *alone, castle, still, will, love, lie, lock*. Love, lie and lock sit in the same sonic family, so the thing he fears, the thing he may be telling and the thing that holds him are tied together by sound as well as sense.
The poem's significance lies in how much it does in so few words. A single metaphor, the man as keep, carries the whole argument about self-protection turning into self-imprisonment. The tangled grammar acts out the confusion it describes, since a mind that lies to itself would speak in sentences that don't quite land. The poem also withholds an ending. It doesn't promise that love will break in or that the man will step out. By stopping on an ellipsis it leaves the gate neither open nor shut, which makes the reader the one who has to decide what lies on the other side.