Let's just start with omnipotence.
A being who is all powerful gets whatever he wants.
So, by virtue of being all powerful an omnipotent being will have whatever character he wants to have. In other words, he'll never be any other way than he wants to be.
Furthermore, a being who is all powerful is not beholden to any laws. A being who is all-powerful makes the laws that bind others, but is not bound by any himself.
That includes moral laws and values. So. an omnipotent beig, by virtue of being all powerful, is the source of moral values and the issuer of moral prescriptions (and all other prescriptions of reason - an all powerful being would therefore have to be Reason). An omnipotent being must therefore be Reason, for if and only if the omnipotent being is Reason will he not be subordinate to anything.
So we now know, just by reflecting on the nature of omnipotence, that a being who possesses it will be Reason and will be the source of moral values and prescriptions. He is not bound by them, because he is their source.
Nevertheless, because an all powerful being will never be any way he does not want to be, that being will always be morally good. Why? Because if the being is the source of moral value, then 'being morally valuable' is just to be a way that the omnipotent being, Reason, approves of. And we know now that because the being is omnipotent he is always what he wants to be. Thus, an omnipotent being will be morally perfect. Not, note, because he will have this or that particular character. But rather because whatever character he has, it is a character he approves of himself having, and 'being morally good' and 'being approved of by the omnipotent being" are one and the same property.
We can see now, then, that an omnipotent being will also be morally perfect. That is, an omnipotent being will also be omnibenevolent.
What about omniscience? Well, as seen above an omnipotent being must be Reason, for then and only then would he be bound by nothing. Now to 'know' something is for one's belief to be one endorsed by Reason, for that is just what it is for a belief to be justified, and 'knowledge' involves having a justified true belief whatever else it involves. Well, if knowledge essentially involves having a belief that Reason endorses, then Reason himself is the arbiter of knowledge and can thus be deemed omniscient.
Thus, an omnipotent being will not only be omnibenevolent, but omniscient also.
In this way, then, it seems clear that these features - omnipotence, omnibenevolence, and omniscience - form a unity. Possession of omnipotence, entails possession of the other two, and others besides.