In the beginning, there was only one law: Don't eat from the tree of the knowledge of good and evil. Adam and Eve sinned by violating this spoken law from God. When they did, they acquired their own sense of good and evil.
Some years later in Genesis 4:
Can someone sin without breaking any law?
Yes, besides sinning against God's spoken or written laws, a person can sin against his conscience. Romans 14:
What is sin?
1 John 3:
Some years later in Genesis 4:
Cain did not offer his best to God. He sinned against his own conscience, his sense of right and wrong.3 In the course of time Cain brought to the LORD an offering of the fruit of the ground, 4 and Abel also brought of the firstborn of his flock and of their fat portions. And the LORD had regard for Abel and his offering, 5but for Cain and his offering he had no regard. So Cain was very angry, and his face fell.
Cain went one step further. He proceeded to murder his brother.6 The LORD said to Cain, “Why are you angry, and why has your face fallen? 7If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. Its desire is contrary to you, but you must rule over it.”
Can someone sin without breaking any law?
Yes, besides sinning against God's spoken or written laws, a person can sin against his conscience. Romans 14:
If you eat something against your conscience even if there is no law against it, it is a sin to you.23 But whoever has doubts is condemned if they eat, because their eating is not from faith; and everything that does not come from faith is sin.
What is sin?
1 John 3:
4 Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness.