What is sin?

John Wesley once looked his mother in the eye and asked a massive question. “Mother,” he said, “can you give me a definition for sin?” That brilliant woman who raised two giants in the faith—John, the preacher, and Charles, the great hymnist—said this: “Son, whatever weakens your reasoning, impairs the tenderness of your conscience, obscures your sense of God, or takes away your relish for spiritual things. In short, if anything increases the authority and the power of the flesh over the spirit, that to you becomes sin however good it is in and of itself.”