The devil is jealous of God's gifts to mankind and endeavors to steal them for his glory. The closer a man draws to God, the more the devil comes against that man for the devil abhors the shining glory of God that emanates from His beloved. It is blinding, annoying and a continually ever present illumination of the devil's filth, his uncleanness and his stench for where the beloved of God are present, so is the sweet aroma and shining glory of God.
"All who desire to live Godly lives in Christ Jesus will be persecuted." 2 Tim 3:12
"Wherein in time past you walked according to the course of this world, according to the prince of the power of the air, the spirit that now works in the children of disobedience" Eph 2:2
There is a worldly course and a heavenly course
A prince has power but his power is trumped by the power of the king.
Air is everywhere and invisible. Air contains fuel for all living things. Satan is the prince of the power of the air.
Death came through Satan. Man willingly gave himself over to the power of Satan and thus death entered into the world. Mankind as the king of the earthly realm relegated his powers to the devil and in return received only that which Satan was able to give which was all that was against God, anti-God and that gift was death and darkness. God in mercy allowed for death to enter into the world for in death, sin is ended yet God also in mercy conquered death so that we might live again forever free from the sin that formally enslaved us.
Saint Paul exhorts us to pray unceasingly. Just as we unceasingly breath to sustain life in this worldly realm, so we must unceasingly pray (which is our breath) for survival in the heavenly realm. Unceasing prayer sustains us in the heavenly realm. When we stop breathing in the worldly realm, we die. When we stop praying in the heavenly realm, we die.