0.) The proof that God exists shows that a necessary cause has contingent effects. Given such a proof, with all its objections met, one goes on to discuss how to speak of God.
1.) A name of necessary cause is true of it either (a) even if its contingent effects are not given or (b) only if its contingent effects are given.
2.) What is given only relative to the contingent is contingent, and (b) is such. Therefore no (b) name taken formally is said of a necessary cause as such.
3.) (a) names are either negations or not, e.g. immaterial or spiritual is a negation while omnipotent or good are not. No negation formally constitutes the substance of anything. Negative names said of God, however, can be taken as indicating the way in which God transcends creation, and so can be said of the divine substance insofar as the negation signifies transcendence or eminence. So while a negation does not formally describe a necessary being, it can describe it eminently.
4.) The distinction between names taken formally and eminently also applies to (b) names. Creator taken formally takes creatures as given, but taken eminently it describes the power or action of the necessary cause, which is not a contingent accident of such a cause. Savior taken formally requires a creature to be saved, but taken eminently it can describe the act of mercy or hesed qua divine attribute and action, which is identical to divinity. Said another way, if we take hesed or rakham (from root raham) as divine attributes describing the divine goodness, they are identical to his essence and so are (a) names even while mercy taken formally involves a relation to the imperfect and broken, and as such is a (b) name.
5.) The original distinction of divine names into (a) and (b) allows a certain (c) class for negations taken formally and not eminently; and it allows for (b) names to be (a) names if taken eminently and not formally.