There is something odd in this claim. If all of God’s actions flow of necessity from God, then that seems to reduce God to some kind of elaborate mechanical contrivance that simply does what it does of necessity – something like the multiverse.
This seems to reduce God’s omnipotence to complete dependence upon some necessary aspect of being, not even rising to the level of human autonomy of will.
That is to say, being itself is a mere brute and necessary fact of being itself.
The entire point being argued is that God isn’t that kind of thing at all, but that omnipotence and omniscience require no constraint on his will, not that every constraint operates on his being to make him impotent by necessity. The nature of God, according to classic theism, requires creative freedom, I.e., that he is free from every encumbrance to do as he wills.
This may seem paradoxical and contradictory, but that would reflect something of the deep mystery of God.
Analogically, as individuals with free will, human beings cannot be reduced to being mere biological machines or wetware. We can originate novel causal activity in the world with full awareness that we are not caused to do so. If I wait here for some cause to propel me to do something, nothing will take place. At the same time, I can choose to do a multiplicity of actions here and now.
It seems to me that if we can’t even explain our own freedom of will, which is so obvious as to be certain to someone with free will, the freedom to act of the omniscient and omnipotent God would be something far less comprehensible to us who cannot even explain the way we ourselves function.
Ergo, any claims about the necessity of God’s actions would seem to be matters we cannot properly address. Nor can we make absolute proclamations about whether God’s actions are “necessary” in the way that you seem so confident that you fully understand.
If you or I have no such confidence regarding our own actions, how can either of us claim to know anything about God’s?