Satan holds no final power over God’s people. Jesus stripped the Devil of his last damning weapon: unforgiven sin.
https://www.desiringgod.org/messages/your-thorn-for-the-shaming-of-satan/
https://www.desiringgod.org/messages/your-thorn-for-the-shaming-of-satan/excerpts/god-holds-satan-on-a-leash