Jehovah reasoned with Cain. “Why are you hot with anger and why has your countenance fallen?” he asked. This gave Cain ample opportunity to scrutinize his feelings and motives. “If you turn to doing good,” Jehovah continued, “will there not be an exaltation? But if you do not turn to doing good, there is sin crouching at the entrance, and for you is its craving; and will you, for your part, get the mastery over it?”​—Genesis 4:6, 7. (See box on page 23.)

Both before and after Abel’s murder, Cain refused to “turn to doing good.” He chose to let sin get the mastery over him, and for this, Cain was banished from the area in which the human family resided. A “sign,” perhaps simply a solemn decree, was established so that no one would avenge Abel’s death by killing Cain.​—Genesis 4:15.

“WHY are you hot with anger and why has your countenance fallen?” With this question, Jehovah kindly reasoned with Cain. He did not force Cain to change, for Cain was a free moral agent. (Compare Deuteronomy 30:19.) Nevertheless, Jehovah did not hesitate to outline the consequences of Cain’s wayward course. He warned Cain: “If you do not turn to doing good, there is sin crouching at the entrance, and for you is its craving.”​—Genesis 4:6, 7.

It is noteworthy that even with this strong reproof, Jehovah did not treat Cain like a ‘lost cause.’ Rather, he told Cain of the blessings that awaited him if he changed his ways, and he expressed confidence that Cain could overcome this problem if he chose to do so. “If you turn to doing good,” Jehovah said, “will there not be an exaltation?” He also asked Cain regarding his murderous rage: “Will you, for your part, get the mastery over it?”