The main concept is that a person can trust God and have just as much morality as anyone else.
This is true but it's the opposite of your main point in your OP.
Without god we have to reason on the consequences of our actions and try to make good decisions.
Christians take ethical positions for ideological decisions regardless of the effects on others. Consider three examples.
1 -Christians object to embryonic stem-cell research on ideological grounds even though it has the potential to relieve a lot of human suffering.
2 - Christians object to loving adult monogamous gay relationships for purely ideological reasons.
3 - Christians object to euthanasia to end the suffering of humans who have no possibility of recovery and who are in insufferable pain.
In these and other examples they appeal to an "absolute" moral duty that exists only in their imagination.
Rational people reason on the consequences of these issues and make objective decisions accordingly.