You see, we actually agree to a point.
I am not trying to market my articles to you for reads and such but I have one that addresses one aspect of this. It is called "Is Christian morality motivated by selfishness" or something like that. That will address one part.
The second part is this, without God, the very concept of "good" and "evil" make no sense. There is no objective standard of good to measure evil against. The scary implications of this is that everything is a matter of opinion. Murder or r**e or molesting kids is not objectively wrong. It's just our opinion and feeling that it is bad. And why can we trust our feelings that they are in fact bad?
You may go, "well, we just know". Then you are admitting there is an objective moral law. And if there is an objective moral law, there has to be an objective moral law giver!
Picture it this way. If there is a 30mph speed limit sign somewhere. You can obey that speed limit without believing in a traffic authority. But it does not change the fact that there is in fact a traffic authority that put that sign there. And in fact it is because of that sign that going 30mph is wrong but that speed and below is right.
Now this does not get you to the Christian God but it does get God in the picture at the very least.
Would recommend my article again for the second point but I could give a quick summary of it if you would rather.
And PS I wouldn't call myself a good person by the way...