A famous idea or paradox is that God could not conceive of something of which he could not do. God of course being used here in the sense of an all-powerful entity, and so since he could not do the above, then he cannot be all-powerful.
I have no idea to what extent this notion has been examined and what excursions of reason it has involved, but a possibly unexamined view is that the thought is being looked at from the wrong linguistic angle. The usual emphasis being that God could not conceive of something of which he could not do.
However, the same sentence can be looked at from a slightly different perspective offering a radically different significance.
God could not conceive of something of which he would not be capable. God is capable of not conceiving of that which he is incapable, and he achieves this by not conceiving of it. Thus an all-powerful entity's absolute mastery is maintained.