You have waited, you always wait, you dumb, beautiful ministers! you novices! We receive you with free sense at last, and are insatiate henceforward, (lines 141-142)
The things of the world were always there in the same form: they were just waiting for somebody like Whitman to come and "discover them." From now on, he says, we're won't be able to live without them. We'll be "insatiate," meaning we'll always be hungry for more and more things of the world. Past, present, and future come together in these lines.