We can thank God, however, that He had mercy on humanity, and because of His mercy, no one has to remain in his or her pitiful condition. Because Jesus’ substitutionary death satisfied the claims of divine justice, all those who believe in Christ can escape from spiritual death and Satan’s captivity because they are no longer under God’s wrath. When we believe in the Lord Jesus, the Holy Spirit comes into our spirits and eradicates Satan’s nature from it, causing our spirits to be born again (see John 3:1-16) and allowing us to become partakers of God’s divine nature (see 2 Pet. 1:4).
Now back to our original question. When the writer of Hebrews stated that Jesus, through His death, rendered “powerless him who had the power of death, that is, the devil,” he meant that the power of spiritual death, which Satan holds over every unsaved person, has been broken for all those who are “in Christ.” We are made spiritually alive because of Christ who has paid the penalty for our sins.
Moreover, because we are no longer spiritually dead and under Satan’s dominion, we no longer have to fear physical death, since we know what awaits us—a glorious eternal inheritance.
Finally, because of Jesus, we have been delivered from suffering the second death, being cast into the lake of fire.
Did Jesus defeat the devil on the cross? No, He did not, because there was no battle between Jesus and Satan. Jesus did, however, render Satan powerless in regard to Satan’s power over spiritual death, by which he holds unsaved people captive in sin. Satan still holds the power of spiritual death over unsaved people, but as far as those who are in Christ are concerned, Satan is powerless over them.
