Which of the two sins, masturbation or free mixing, is more harmful for the one who commits it, such that he should abstain from it?

It is not permissible for a person to choose between two reprehensible acts; rather, he must abandon both of them. Allah Almighty has commanded us to abandon sin, both its outward and inward forms, meaning both its small and large manifestations, its secret and its open ones. Just as the Prophet, peace and blessings be upon him, qualified the aspect of commanding with ability, he left the aspect of forbidding unrestricted. Therefore, what is forbidden must be abandoned completely and immediately, because what is required is continuous abandonment.