What Accounts for God's Greatness?
For classical theists, God's greatness is not about moral excellence or based on various intuitions people have about “great-making properties.” God does not even have properties, properly understood. Instead, God's greatness arises from the metaphysical commitment that being and goodness are convertible, coupled with the claim that God is purely actual, subsistent being.
As purely actual, subsistent being, God has no intrinsic passive potency to fulfill, which is necessary to reach some higher state of greatness or perfection. God – whatever else God is – is already the greatest God can be, as a matter of metaphysical necessity.
By understanding God as purely actual and devoid of any potentiality, classical theists affirm that God's greatness is inherent and unchangeable, rather than something that could be improved or perfected over time.
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This is just to clarify my thoughts.
Every effect has a cause and often there are multiple causes for a specific event or series of related events. The effect/event must somehow exist within its causes.
So if there is an initial cause for all that we see, everything that exists must be within this original cause in some form. Otherwise what we see would partly or wholly just pop into existence from no previous source.