Who was the first murderer in the Old Testament?

Cain was the first murderer in the Old Testament, killing his brother Abel in Genesis 4.

Cain and Abel were sons of Adam and Eve. Cain worked as a farmer, while Abel kept flocks. Each brought an offering to God, but the narrative says that Abel’s offering was accepted while Cain’s was not. Cain became angry and jealous, and he murdered Abel in the field.

Afterward, God questioned Cain, who denied responsibility with the famous question, “Am I my brother’s keeper?” Cain was punished by being made a restless wanderer, unable to rely on the soil as he had before. Genesis also describes a protective mark placed on him so that others would not kill him in revenge.

Cain is sometimes confused with Lamech, another descendant of Adam who later boasts of killing a man. Adam was the first human in Genesis, but not a murderer, and Abel was the first murder victim rather than the killer. The story is also retold in Islamic tradition, where Cain and Abel are called Qabil and Habil.