In Of Mice and Men, is the relationship between George and Lennie one of friendship, or obligation on George's part?What evidence can you find to...

While it is difficult to certain about George and Lennie's relationship in the first chapter of Of Mice and Men, the reader later realizes that theirs is, indeed, a true friendship.  However, if the response is to based solely upon the narrative of only the first chapter, indications are only that George feels some obligation to care for Lennie, and he gives this care somewhat begrudgingly.  Thus, the relationship seems similar to an older brother having to take care of a little brother:

'...if I was alone, I could live so easy.  I could go get a job an'work, an' no trouble.  No mess at all, and when the end of the month come I could take my fifty bucks and go into town and get whatever I want.  Why, I could stay in a cat house all night.  I could eat any place I want, hotel or any place, and order any damn thing I could think of...An whatta I got,...I got you!...You keep me in hot water all the time.'

But, after this tirade which sounds much like an older brother's complaints, George's anger leaves him suddenly; he looks at the fire "ashamedly."  And, when Lennie asks if George wants him to go away, George asks, "Where the hell could you go?"  Then, when Lennie's feelings are hurt, George tells him,

'I want you to stay with me, Lenie. Jesus Christ, somebody'd shoot you for a coyote if you was by yourself.  No you stay with me.  Your Aunt Clara wouldn't like you  running off by yourself, even if she is dead.'

Clearly, George is irritated with Lennie, but like an older brother he may not like Lennie, but he feels an obligation toward him since he has promised Lennie's aunt he would look out for her nephew, and since Lennie's child-like nature makes his fond of the man.  This child-like nature also gives George something:  the dream.  With Lennie, as an older brother can, George can still believe in the unbelievable.  And this dream of owning a ranch of their own is what motivates George to keep working.  Lennie gives George a reason to live.

So, when Lennie says he can go away if George wants him to, George tells him to be quiet.  George needs Lennie to talk to, to share their dream. Their relationship is both one of obligation and of a begrudging friendship, as George, with Lennie,  has something to hold onto to give his life meaning.