Whether God alone is the cause of grace?

Objections

Objection 1 : It would seem that God alone is not the cause of grace. For it is written (Jn. 1:17): "Grace and truth came by Jesus Christ." Now, by the name of Jesus Christ is understood not merely the Divine Nature assuming, but the created nature assumed. Therefore a creature may be the cause of grace.
Objection 2 : Further, there is this difference between the sacraments of the New Law and those of the Old, that the sacraments of the New Law cause grace, whereas the sacraments of the Old Law merely signify it. Now the sacraments of the New Law are certain visible elements. Therefore God is not the only cause of grace.
Objection 3 : Further, according to Dionysius (Coel. Hier. iii, iv, vii, viii), "Angels cleanse, enlighten, and perfect both lesser angels and men." Now the rational creature is cleansed, enlightened, and perfected by grace. Therefore God is not the only cause of grace.