"From the very beginning of the great controversy in heaven it has been Satan's purpose to overthrow the law of God." GC 582
WHY?
Because God's law is the foundation of his government. To overthrow it would be to overthrow God's government.
The law expresses the moral integrity of the cosmos and to overthrow that law would be to overthrow the moral order of creation.
But what is morality?
Morality involves the power of thinking and the ability to choose. Morality differentiates between right and wrong.
But what is right and what is wrong?
Is it love -- just love?
But what defines love?
"Love can't exist without freedom, moral freedom. And moral freedom can't exist without law, moral law".
The law of God is as sacred as Himself. It is a revelation of His will, a transcript of His character, the expression of divine love and wisdom. Through the ages that law has been preserved as the highest standard of morality. Not all the inventions of science or the imaginations of fruitful minds have been able to discover one essential duty not covered by this code. {ST, February 1, 1910 par. 6}
God's law is the security of life and property, of peace and happiness. It was given to secure our present and eternal good. A thoughtful kindness runs through every enactment. Each commandment is an enactment of mercy, love, and saving power. {ST, February 1, 1910 par. 7}
Link to Introduction to this quarters lessons