When God created Adam and Eve, and placed them in the Garden, He also provided them with food. Not only did He provide them with their daily food, hanging from the branches of all the trees in the Garden, He also provided them with sacramental food, the food that was fruit of the Tree of Life. Only one tree was prohibited to them, the Tree of the Knowledge of Good and Evil, not two trees. And that one tree was only prohibited for a time, until after they had passed their probationary test.
But the point to be made is that God always feeds His people. When He created us, He created us needing food, and He provided the food along with the need.
It is the same with us. All the food we receive is from God—this is why we thank Him for it before every meal. We bow our heads and acknowledge that we are sustained, necessarily and constantly, by His provision. But the same thing is true here.
Not only does God supply us with our physical food, so He also supplies us with our spiritual nourishment. This is the cup of the new covenant, and the new covenant is the covenant of life and grace. This is our Tree of Life.
But sustenance does not come as a result of simply eating. Within the covenant, there is no such thing as automatic blessing. When we approach the Tree of Life in faith, we are also necessarily staying away from all those things that God has warned us away from. If we try to continue to eat from prohibited places, and come here as well, then by definition we are not coming here in faith.
Faith is not an exact synonym with obedience, but faith always obeys. Faith is never disobedient. If it is disobeying, then you know right away it is not faith. And so we speak freely of an obedient faith, a faith which simply takes God at His word, and does not try to eat from this Table and the prohibited tables set by idolaters who would lure us away from this, our first love. Let us now — in obedient faith — eat and drink.