Whether the sacraments are instituted by God alone?

Objections

Objection 1 : It seems that the sacraments are not instituted by God alone. For those things which God has instituted are delivered to us in Holy Scripture. But in the sacraments certain things are done which are nowhere mentioned in Holy Scripture; for instance, the chrism with which men are confirmed, the oil with which priests are anointed, and many others, both words and actions, which we employ in the sacraments. Therefore the sacraments were not instituted by God alone.
Objection 2 : Further, a sacrament is a kind of sign. Now sensible things have their own natural signification. Nor can it be said that God takes pleasure in certain significations and not in others; because He approves of all that He made. Moreover, it seems to be peculiar to the demons to be enticed to something by means of signs; for Augustine says (De Civ. Dei xxi): "The demons are enticed . . . by means of creatures, which were created not by them but by God, by various means of attraction according to their various natures, not as an animal is enticed by food, but as a spirit is drawn by a sign." It seems, therefore, that there is no need for the sacraments to be instituted by God.
Objection 3 : Further, the apostles were God's vicegerents on earth: hence the Apostle says (2 Cor. 2:10): "For what I have pardoned, if I have pardoned anything, for your sakes have I done it in the person of Christ," i.e. as though Christ Himself had pardoned. Therefore it seems that the apostles and their successors can institute new sacraments.