The acts of sin (or the way of Egypt under the slave on man or the carnal nature...as this is what Leviathon is - it's not just a literal context. It's also referring metaphorically - Ps. 74:12-20) dies when a son of God truly walks out of the slavery in bondage to sin (the old man and into the new nature in Christ); into the fullness of Christ Jesus through full repentance from the old nature (the mature state, 1 Cor. 15:52-58; Col. 1:13-20; 1 Pet. 1:15-16, 20-25; 1 Pet.2). That's when it's dead. Those that have not come into this fullness may still walk under the bondage of it's ways (the carnal nature/Egypt, sin, death). But when you have come through into the fullness of God's will abiding in and through you by the leading of the Holy Spirit in all things...than Leviathon's dead...sin and its ways are dead to you...you've chosen life eternal, which is through Jesus Christ, by the leading of His Holy Spirit into God's will in all areas of your life (Prov. 3:5-6; Rom. 8:14-15).