Every Christian faces three enemies: the world, the flesh and the devil. All three can be seen in Genesis 3.
The world refers to the system humanity has put in place to get by without God. It came to life when Adam and Eve sewed fig leaves together to cover their nakedness (3:7). When the couple disobeyed God and ate the forbidden fruit, they knew something was wrong. They tried to fix the problem with completely inadequate fig-leaf clothing.
The flesh refers to sinful human nature. After they sinned and were interrogated by God, Adam and Eve played the blame game. While they reluctantly confessed to their evil deed, they also implicated another. Pride was at the forefront of sin in the Garden of Eden.
The devil is Satan, the serpent who deceived Eve.
The world, the flesh and the devil have ever since worked together to oppose God and make life difficult for believers. Yet the believer is not without hope. Quite the contrary. As also evidenced in Genesis 3, believers have access to God's amazing grace and power. God took the initiative to reconcile man after the fall, he promised deliverance from the devil via the Seed of the woman, he provided an adequate covering for humanity via the death of an animal, and then he protected humanity from further tragedy by restricting their access to the tree of life.
With God on our side, no one can effectively stand against us (Romans 8:31)