Marsilio Ficino, in chapter 4 of his De Christiana Religione, argues that God does not reject all forms of human worship, even those performed by other religions. Rather, God approves of man’s worship of him and he does not punish every form of false worship equally. Though all forms of religious worship derive, in some sense, from God’s grace, ultimately only the worship of the pious Christian is pure because it is performed out of charity, that is, for the love of God above all else. He will explain this in further detail in the coming chapters.
Every religion has a certain amount of good provided that it is directed to God himself the creator of everything, [but] Christianity is pure [religion].
Nothing displeases God more than to be despised. Nothing pleases him more than to be worshipped. God punishes those men more lightly who transgress some aspect of the divine law, but blasts with lightening from his Kingdom those who revolt through ingratitude, malice, and pride. Therefore, divine providence does not permit there to be any region of the world utterly lacking in any religion at any time, although it permits different rites of worship to be observed in different places and times. Perhaps, in fact, varieties of this sort, having been ordained by God, produce a certain extraordinary rectitude. It is a better act to honor the highest King in truth than to honor him with various bodily gestures. King Alexander [the Great] was honored by as many nations as he commanded when he either went to them himself or sent legates. And on the whole he, in a certain measure, commended that which was done for his glory, though he held some to be more pleasing than others. The same should be observed with the King of the world. He would prefer to be worshipped in any way or inappropriately, in a human way, rather than not be worshipped at all due to arrogance.
Indeed, to those men who are unrestrained but in a certain measure submissive, God either corrects as a father or alternatively he afflicts them lightly. The impious, on the other hand, that is, those who are completely ungrateful and voluntarily rebellious, he dismisses and torments as his enemies. For, though God does not completely reprove all human worship as voluntary impiety but receives it by his grace, nevertheless, what kind of [worship] does God approve more than any other, no indeed, [what is the] only one [that he truly approves]? 1God in himself is the Highest Good, the Truth of everything, the Light and Good-will of minds. Therefore, they worship God better than the rest, indeed they alone worship him sincerely, who diligently honor [venerant] him by their actions, by the truth and goodness of their speech, by the clarity of their minds (which they are capable of) and by charity (which they should [have]). Truly, Christ the Instructor of life [vitæ magister] and his disciples, as we shall demonstrate, give direction to the kind of people who worship [adorant] God in this way. 2