9 And the LORD said unto Moses, I have seen this people, and, behold, it is a stiffnecked people:10 Now therefore let me alone, that my wrath may wax hot against them, and that I may consume them: and I will make of thee a great nation.
God gave Moses a choice. A) Leave him alone so that he may consume them or B) stay with him (opposite of leave him alone).
Moses used the choice to make a case for his people and to "not leave him alone". Moses volunteered to be an advocate for his people. Later in 33:18 God tells Moses he will "show mercy on whom I will show mercy". Clearly he is not leaving it to Moses's intercession.
"God gave Moses a choice."
God always gives a choice--starting with: "...Thou shalt not eat of it...."
But, to take God's word at face value, what He said was:
"Now therefore let me alone, that my wrath may wax hot against them, and that I may consume them: and I will make of thee a great nation."
Did God mean what He said here? This is an important point. Was He lying? Bluffing? Playing games? Or, did He mean what He said, and THEN change His mind later?
How can a God that knows everything in advance, every single detail, CHANGE His mind? Change is, well, CHANGE. You know, as in different than moments before.