To kill a person or any other living thing means taking away the source of all their strength, vitality, and power, so they can no longer act or exert any of their abilities. The same idea applies here. Indwelling sin is compared to a living person called "the old man," with his faculties and properties, wisdom, cunning, subtlety, and strength. The apostle says this must be killed, put to death, and overcome—that is, have its power, life, vitality, and strength to produce its effects removed by the Spirit.
