Consider Aristotle’s view of virtue and happiness (eudaimonia, in Greek). Happiness — a deep, lasting happiness — is a life lived according to virtue, Aristotle writes. Morality can be seen as the roadmap to human happiness.
Over thousands of years, Christianity, building on the traditions of the Jews and ancient civilizations such as the Greeks, has tried to understand human nature ± — through experience, reason, and revelation. From that picture of the human soul, the Church has tried to craft a roadmap.
We need a roadmap because life is full of obstacles and pitfalls that we typically can’t see beforehand on our own, but which are well-known in prior human experience. Walking directly towards what we think we want can often be perilous to our happiness. Sacrifice, patience, and struggle are often required.