You have waited, you always wait, you dumb, beautiful ministers! you novices! We receive you with free sense at last, and are insatiate henceforward,
Hold on – we're diving even further into the weeds of philosophy.
The things of the world have been waiting for us to view them with fresh eyes, or "free sense." Once we have seen them in the right way, we are "insatiate"; literally, we can't get enough. We're hungry for more things. More! MORE!
Incidentally, there's a slight pun here, because the speaker is on a ferry and there are probably real people "waiting" at the other end for the passengers to arrive. But the speaker is addressing not just real people, but all the things from section 24. These things are "dumb" because they aren't literally talking.
Using another comparison to religion, the speaker calls the things "ministers" and "novices." This means they are like both teachers in a religious order and also members-in-training.
Not you any more shall be able to foil us, or withhold yourselves from us, We use you, and do not cast you aside—we plant you permanently within us, We fathom you not—we love you—there is perfection in you also,
Like a slippery fish trying to wriggle away, the basic things in the world have eluded or "foiled" us in the past.
But not this time. We're going to use these things without throwing them away. We're going to "plant" them inside us like seeds. Even though we don't fully understand or "fathom" these things, we love them anyway and now they are perfect.
Whitman was sometimes compared to a religious prophet or mystics, and in these lines, it's easy to see why.
You furnish your parts toward eternity, Great or small, you furnish your parts toward the Soul.
All the things of the world provide or "furnish" the parts that make up eternity. (What is eternity? Sorry, but Whitman isn't going to answer all your deepest questions here.)
Returning to the distinction between "great and small" – earlier he used these words to describe the roles of actors – he says that everything, no matter what size, provides the parts that make up the unified Soul.
Or is it the individual Soul? Or are they both the same thing? Here we thought we had answers, but we're left only with more questions.