I will be to you a god

Exodus 6:7 says, "And I will take you to me for a people, and I will be to you a God: and ye shall know that I am the LORD your God, which bringeth you out from under the burdens of the Egyptians." He will be to them a god? Sounds like someone is playing favorites? Doesn't he love us all? Didn't he create us all? Shouldn't we all be his people, I mean aren't we all sons of Noah? The flood supposedly wiped out everything but those on the arc so why would he choose favorites?