Rather strangely, it is the destruction of the city that is charted in the final pages of the novel, once Montag has managed to escape the Mechanical Hound, that is the sign that tells Montag that he is welcome in the world because he has something to offer and contribute to its rebuilding. Having been an outcast who doesn't fit in to the social order of the city, Montag's identity and role in life is now transformed by the city's destruction. The rebuilding of society that will need to occur will depend upon the book people and the kind of knowledge that they are able to bring upon the metaphorical rising of the phoenix from the ashes of the destroyed city. Note what Montag thinks of his changed situation:
And someday, after it sets in us a long time, it'll come out our hands and our mouths. And a lot of it will be wrong, but just enough of it will be right. We'll just start walking today and see the world and the way the world walks around and talks, the way it really looks.
Montag now has something concrete to offer the world, and the way in which he and the book people look forward to being part of the process of rebuilding indicates the way that they can belong and be welcomed by the world that once shunned them.
montag believes that his escaping of the mechanical hound is the sign he will now be welcomed , now that he must remember a book to help the new society of its becoming he feels welcomed as he is partly needed and wanted.
It says on page 143 (or at least in my book) :
"A cool glass of fresh milk, and a few apples and pears laid at the foot of the steps.
This was all he wanted now. Some signs that the immense world would accept him and give him the long time he needed to think all the things that must be thought.
A glass of milk, an apple, a pear."
I know it's not a very philosophical answer, but I that's what the book says. A glass of milk, and a few apples and pears.