We proceed to the first article thus:

1. It seems that God is not the sole cause of grace. For it is said in John 1:17 that "grace and truth came by Jesus Christ," and the name Jesus Christ means the creaturely nature assumed as well as the divine nature which assumed it. It follows that what is creaturely can be the cause of grace.

2. Again, the sacraments of the new law are said to differ from those of the old in this respect, namely that the sacraments of the new law are causes of the grace which those of the old law only signify. Now the sacraments of the new law are visible elements. It follows that God is not the sole cause of grace.

3. Again, according to Dionysius {Coel. Hier.3, 4): "angels purge, enlighten, and perfect both lesser angels and men." But rational creatures are purged, enlightened, and perfected through grace. It follows that God is not the sole cause of grace.

On the other hand: it is said in Ps.84:11: "the Lord will give grace and glory."

I answer: nothing can act upon what is above its own species, since a cause must always be greater than its effect. Now the gift of grace exceeds every capacity of nature, since it is none other than a participation of the divine nature, which exceeds every other nature. It is therefore impossible for any creature to be a cause of grace. Hence it is just as inevitable that God alone should deify, by communicating a sharing of the divine nature through a participation of likeness, as it is impossible that anything save fire alone should ignite.

On the first point: the humanity of Christ is "an organ of his divinity," as the Damascene says (3 De Fid. Orth.15). Now an instrument carries out the action of a principal agent by the power of the principal agent, not by its own power. Thus the humanity of Christ does not cause grace by its own power, but by the power of the divinity conjoined with it, through which the actions of the humanity of Christ are redemptive.

On the second point: just as in the person of Christ humanity is the cause of our salvation through the divine power which operates as the principal agent, so it is with the sacraments of the new law. Grace is caused instrumentally by the sacraments themselves, yet principally by the power of the Holy Spirit operating in the sacraments.

On the third point: an angel purges, enlightens, and perfects an angel or a man by instruction, not by justification through grace. Wherefore Dionysius says {Coel. Hier.7): "this kind of purging, enlightening, and perfecting is nothing other than the acquisition of divine knowledge."