Why does God bless you?

I was recently offered a new job.  When telling a friend about it, she told me that she knew I would get it.  Her reason was that she knew that God would bless me because of the things I have been doing diligently for God.

Really?  Is this why God blesses someone?  What do you think?

Is it because of our merit that we are blessed?  Is it because we have worked hard that we get the results we desire?  Or is it our service for God that lets us gain favour?

Perhaps I got the job because my friend gave me a good reference.  Perhaps it was something at the job interview.

Perhaps, God blessed me because He chose to - not because of anything I have done or did not do.

What do you think?  Why?