God reveals to His prophets that there are moral absolutes. Sin will always be sin. Disobedience to the Lord’s commandments will always deprive us of His blessings. The world changes constantly and dramatically, but God, His commandments, and promised blessings do not change. They are immutable and unchanging. Men and women receive their agency as a gift from God, but their liberty and, in turn, their eternal happiness come from obedience to His laws.
Lesson taken from the talk, "Obedience to the Law is Liberty" by Elder L. Tom Perry, April 2013 General Conference. Lesson given by Sister Shauna Hegwer.