Robert D. Hales: Warning lights of a personal nature are activated for many reasons. For example, the use of alcohol, tobacco, drugs, or pornography would turn on warning lights, because when we choose to use these substances, we become slaves and our moral agency is limited.
We must be prepared with preconditioned responses to reject these things when they are offered to us, or we will jeopardize our right to have the Spirit to guide us and direct us and our ability to return to our Heavenly Father with honor.
(Ensign, June 1999, p. 10)
