Do you think Satan being bound to the earth can be linked to Satan being bound for the millennium?
The advent of Christ is definitely when Satan was bound. I believe Satan and his angels were cast out of heaven and bound to the earth when Christ was born. IMO that marks the beginning of Christ defeating Satan, but the birth of Christ only bound Satan to the earth. Because Scripture seems to show us it was the cross where Christ made atonement for sin and defeated death that bound him in a pit that he should deceive the nations no longer. Satan had the ability to deceive the nations, holding them in bondage to fear of death until Christ defeated death by resurrecting from the grave. After His death and resurrection, the Gospel was sent unto all the nations of the world in the power of the Holy Spirit. That's when the message of the cross and resurrection proved more powerful than Satan, because Christ descended into that place of Old called the bosom of Abraham and set those Old Covenant captives of the grave free, taking them with Him when He ascended to heaven. Since Christ defeated death those who hear the Gospel preached in the power of the Holy Spirit, faith (believing in Christ) takes away fear of death because Christ gives eternal life to whosoever believes.