In just four lines, the speaker sets out for the Indies, a voyage that sounds like both a trade trip and a holy one. "On business with Christ" is the odd, sharp phrase here. It folds commerce and religion into a single errand, as if saving souls and making money were the same job. The title, "Civilizing mission," points the same way, and its quotation marks suggest the poem doesn't take that phrase at face value.
Then the speaker turns the joke on himself. He calls himself "an ape / not knowing the dirt." The word "ape" flips the usual colonial insult: the so-called civilizer is the clumsy imitator, and he doesn't even understand the ground he's about to walk on. The tone is dry and self-mocking, with an uneasy edge. The speaker seems aware of his own ignorance and hypocrisy, yet he sails on anyway. What lingers is a sense of confident purpose built on very little knowledge.