The Perfectly Good God
The Oxford Handbook of Philosophy of Religion (p. 21):
The idea that God is perfectly good, like the idea that God is all-powerful, is connected to the view that God is a being who deserves unconditional gratitude, praise, and worship. For if a being were to fall short of perfect goodness, it would not be worthy of unreserved praise and worship. So, God is not just a good being, his goodness is unsurpassable. Moreover, according to the classical theology of the principal religions of the West, God doesn't simply happen to be perfectly good. As with his absolute power and total knowledge, it is his nature to be that way. God necessarily could not fail to be perfectly good. It was for this reason that we observed in the section on God's power that God does not have the power to do what would be morally wrong for him to do. For intentionally doing what is morally wrong for one to do is inconsistent with being perfectly good. It is worth noting that in saying that God is essentially good, we are doing more than saying that necessarily God is a perfectly good being. We are saying in addition that the being who is God cannot cease to be perfectly good. Necessarily, a bachelor is unmarried. But someone who is a bachelor can cease to be unmarried. Of course, when this happens (the bachelor marries), he no longer is a bachelor. Unlike the bachelor, however, the being who is God cannot give up being God. The bachelor next door can cease to be a bachelor. But the being who is God cannot cease to be God. Being a bachelor is not part of the nature or essence of a being who is a bachelor. But being God, and thus being perfectly good, is part of the nature or essence of the being who is God.
We can make the following statement from the above reading:
Premise 1: The idea of perfect goodness of God says it is the nature of God to be perfectly good. In other words, God cannot be any other way.
Another way to state this is:
Premise 2: It is impossible for God to be anything but perfectly good. Logically, anything God does or says has to be perfectly good.
Conclusion:
If a god says or does something that is not perfectly good, then the god cannot be the perfectly good God.
What do we mean by perfectly good God? That God is morally perfect.
Is Yahwey, god of the Bible, eligible to be a perfectly good God? Not if he has said or done something that is not perfectly good.
The Oxford Handbook of Philosophy of Religion (p. 15):
In the Old Testament of the Christian Bible, to cite just one example, God, through his prophet Samuel, orders Saul to totally exterminate a tribe of people, the Amaleks, to “kill both man and woman, infant and suckling, ox and sheep, camel and ass” (1 Samuel 15). Upon receiving his orders from on high Saul dutifully kills the Amalek men, women, children, and infants, but takes for himself and his men the best of the oxen, sheep, and lambs. On learning of this, God is angry and regrets making Saul king because, although Saul carried out his order to kill all the men, women, children, and infants, he did not follow God's order to slaughter all the livestock as well. On reading such a story one can hardly avoid the conclusion that the being giving such orders is viewed as a tribal deity rather than an omnipotent, perfectly good, omniscient being.