To say someone is moral is to say that the terms "good" and "evil" apply to them in a meaningful way. In other words, when you say that someone is good, you are saying that their thoughts and actions have been consistent with a standard. This standard is what morality is. To accept the idea that one can be good or evil while rejecting the notion that they are moral is to commit a "Stolen Concept Fallacy"*.
So where does that standard come from?
Both those who say there is an absolute standard applicable to both God and us and those who say that God is the standard and it springs from his own personality suffer from similar logical problems.
1) Those who say it comes from God's own nature and is therefore consistent answer the problem of coherence but defer the problem of arbitrariness to God's own nature. If it were in God's nature to randomly murder babies or send shooters into schools, then we ought to perceive such things as good things. But no one perceives such things as good. So the idea that the standard of good comes from God's nature doesn't accord with common sense. Common sense tells us that (at least in some cases) the goodness or evil of some situation speaks for itself.
2) Those who say that the standard of morality is absolute, require that there be a law written somewhere that somehow transfers itself to our awareness whenever we see or do things and allows us to judge them. The origin of such a standard has to my mind never been explained.
In both cases, the existence of some kind of moral standard suffers from a serious practical defect, namely that there is no language we can use to codify such a standard without descending into irrelevance and contradiction. For example those who say that God's own character is the source of morality would probably suggest that whether some action is right or not is answered by reference to what God would do in that same situation. However, that kind of answer is by definition always hypothetical. The fact is that it is you in that situation, not God.
And for those who assert there is an absolute standard, any rules they seek to impose on some situation quickly develop exceptions, like the lying versus protection ethics that have already been discussed ad infinitum. I think it is fair to say that any conceivable rule you could formulate would be valid at most on 50% of the situations where it could apply. Which means that if one follows these rules legalistically, one will be making errors of judgement 50% of the time.
