Origin and Application:
Cain, the firstborn son of Eve and Adam, murdered his younger brother Abel. This is the first account of murder in the Bible. Later, Abel’s blood cried out to God from the ground. God heard his cries and put a curse on Cain as a punishment – “When you work the ground, it will no longer yield its crops for you. You will be a restless wanderer on the earth.” (Genesis 4:12)
Cain was very worried that he would be killed by others who find him. So God put a mark on Cain so that no one who found him would kill him.