The speaker is sitting in church, half asleep, and the poem drifts the way a dozing mind does: from the pulpit to a memory, then to money. The memory is the strangest part. A "large man of small mien," someone physically big but meager in spirit or manner, once told the speaker that their convulsions pleased the Lord. It's an odd, unsettling thing to hear. The poem doesn't say what the convulsions were, but the speaker recalls the remark with a flat, wry calm, as if still turning it over.
Then the poem slips sideways. Going over the accounts, the speaker finds "a sea in my purse," which could mean a flood of coins or, just as easily, a bewildering emptiness, something vast and shapeless where money should be. The mood is dreamy and dryly funny, with an undercurrent of unease. Sermon, suffering, and spending blur together, and the speaker seems both bored by religion and quietly haunted by what it has said.