“Why do Fundamentalists and Evangelicals reject the plain, literal interpretation of John 6? For them, Catholic sacraments are out because they imply a spiritual reality—grace—being conveyed by means of matter. This seems to them to be a violation of the divine plan. For many Protestants, matter is not to be used, but overcome or avoided.”
No, Protestants don’t object because of “matter”; we are not manicheanists. We object because this view put grace subject to works, in that in order to obtain grace, you must first do certain works. The Bible tells us that the chronology is the opposite. First you recieve grace, and then your spirit is regenerated, enabling you to do good works.
You act first to do works such as Baptism, Confirmation, Receiving the Holy Eucharist, Confession, Marriage and then you receive the graces from God. Since the time of the Council of Trent theologians almost unanimously have taught that the sacraments are the efficient instrumental cause of grace itself.
The Church teaches that there is a difference between actual grace and sanctifying grace. An easy way to understand actual grace is to remember that it enables us to act. It is the strength that God gives us to act according to his will. Sanctifying grace is a state in which God allows us to share in his life and love. When we speak of being in the state of grace, we mean the state of sanctifying grace. There is no mortal sin in us. This grace comes to us first in baptism and then in the other sacraments.