I think you could draw a parallel example in what Jesus said about the whole Law resting on two commandments: To love God above all things and to love your neighbor as yourself. You might say that Catholicism rests on these things.
To say, as you suggest, that “do unto others…” sums up Catholicism is to ignore the first part to which Jesus refers…that is, the part about loving God. It all has to begin with a love of God. We cannot just focus on how we love others (as important as that is) and say that our relationship to God is insignificant. Our relationship with God involves a sacramental bond of Love. We need the sacraments to bask in his Love.
And also, we must remember, that while Jesus pointed to these two commandments of love as the starting point for the Law, that did not stop Him from saying a whole lot about other things as well, like baptism, the Eucharist, marriage, unity in belief among Christians, etc. And the Bible calls us to be One Body in Christ, united in faith. This implies unity of doctrine.
Doing to others as we would have them do to us is an outgrowth of the law of Love that Jesus preached. But Jesus was also the embodiment of Truth. To love God we must know the Truth of God. To love our neighbor we must know our neighbors value in God’s eye. To achieve this we must be open to receiving what God has revealed about Himself. And that, of course, means knowing what the Church teaches in its doctrines and dogmas, which illuminate our understanding of God.
We must surely treat others with love and respect. But it begins with God. The doctrines and teachings of Catholicism should not be seen as added baggage. They are God’s way of reaching out to us through His Church, and our way of reaching out to Him, so that He comes first in Love.
Thomas
