It avails not, neither time or place – instance avails not, I am with you, you men and women of a generation, or ever so many generations hence, I project myself – also I return – I am with you, and know how it is. (lines 20-22)
You could imagine the speaker as a character in a bad soap opera (the best kind) declaring to his lover, "Nothing can keep us apart!" Time and distance are not obstacles for him. Through good times and bad, he's with us and can relate to life's joys and defeats. He "knows how it is." Does this idea have serious implications, or is it just heart-warming fluff?
These, and all else, were to me the same as they are to you, I project myself a moment to tell you – also I return. (lines 50-51)
Whitman's idea of friendship is built on shared experience: camaraderie. In this poem, the way he creates this mutual experience is by telling us about his experiences and then pretending that we did the same thing.
What is it, then, between us? What is the count of the scores or hundreds of years between us?
Whatever it is, it avails not – distance avails not, and place avails not. (lines 57-59)
Again with the "nothing can keep us apart" business. But, seriously, this poem was written close to the beginning of the Civil War, and the ability to break down the walls "between" people seemed like an urgent project. Incidentally, we're in good company as "imaginary friends" of Whitman: he had the same relationship with President Abraham Lincoln, in that the two men both hugely admired each other but never actually met.
I was called by my nighest name by clear loud voices of young men as they saw me approaching or passing, Felt their arms on my neck as I stood, or the negligent leaning of their flesh against me as I sat, Saw many I loved in the street, or ferry-boat, or public assembly, yet never told them a word, (lines 82-84)
Whitman was all about the physical and emotion bonds between men. In the 19th century, it wasn't uncommon for men to openly show affection between one another in the streets. Notice, however, that being friends with someone doesn't mean you tell them everything. The speaker doesn't tell his comrades about his "abrupt curious questionings," of whatever it is he means here by "a word."
Closer yet I approach you, What thought you have of me, I had as much of you – I laid in my stores in advance, I considered long and seriously of you before you were born. (lines 89-91)
The speaker keeps positioning himself to get closer and closer to us until – ah! – he's right next to us. He also provides a great pick-up line: "I've been thinking about you since before you were born." What a lady-killer. Or gentleman-killer.
Consider, you who peruse me, whether I may not in unknown ways be looking upon you; (line 123)
The speaker turns the tables on the reader. He's all, "You think you're reading me, but maybe I'm the one who's reading you." But don't worry: having read a lot of Whitman, we can say for sure that he won't judge you too harshly. Even if you sing really off-key songs in the shower, he'll still be your friend.
Not you any more shall be able to foil us, or with- hold 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, (lines 143-145)
Although he has been acting friendly toward non-human things throughout the entire poem, at the end he really lets loose with his love for "things." After all, inanimate objects and solids and fluids need friends, too! Even though he doesn't fully understand or "fathom" these things, he thinks they are perfect just the way they are.