Grappling with the dangers of the world, the flesh, and the devil has always been a prominent aspect of Christian thinking and living:
In his helpful Golden Booklet of the Christian Life, John Calvin asserts, "Nothing is more difficult than to forsake all carnal thoughts, to subdue and renounce our false appetites, and to devote ourselves to God and our brethren, and to live the life of angels in a world of devils."
Centuries earlier, Peter Abelard wrote in his Expositions that, “There are three things which tempt us, the world, the flesh, and the devil.”
Thomas Aquinas refers to the world, the flesh, and the devil in his Summa Theologica as “the great adversaries of our souls.”
The phrase probably entered popular use in English through the Book of Common Prayer, which utilizes the phrase in its Daily Litany, “From all the deceits of the world, the flesh, and the devil, Good Lord, deliver us.”
But, this triad of dangers is actually first clearly articulated in Christ’s parable of the sower in Matthew 13, Mark 4, and Luke 8. There the Lord provides us with three illustrations of unproductive soil: the seed choked by thorny soil represents the cares of the world; the seed that springs up in rocky soil but then withers represents shallow and carnal believers who live according to the flesh; and the seed that fell on pounded soil, along paths and roadsides, only to be devoured by the birds represents the Devil’s voracious wiles.
The Apostle Paul also describes these three dangers in Ephesians 2:1-3, “You were dead through the trespasses and sins in which you once lived, following the course of this world, following the ruler of the power of the air, the spirit now at work among those who are disobedient. For, all of us once lived among them in the passions of our flesh."
And, the Apostle John alludes to them in 1 John 2:16, “For all that is in the world—the desires of the flesh and the desires of the eyes and pride in possessions—is not from the Father but is from the adversary.”
The point is: ours is a comprehensively fallen universe—it’s not just the devil we have to watch out for; it’s not just the devil and me; it’s everything, everywhere, all the time.