And You Say?

Romans 4:3 says Abraham believed God.

For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.  source

What if the Text read Abraham believed in GOD; is there a difference?

If we could poll the masses, I think we would find that millions of people would tell us they believe in GOD.
But do they Believe GOD?

Is there a difference?
And which are you?
In or believe Him?