well if you don’t believe the devil, the personification of evil, is at work in the world, you might want to watch a steady diet of fox news or CNN.
If you believe that God is all good, and that he created his creatures with free will to love him in return, it must follow that it is possible for his creatures to turn against him in mind, heart and will. In that case they would remain in a state of non-good, separated from God, so such a state must exist, and every choice against God’s will to some degree is a choice for that state.
Temptations come in 3 ways, the world, the flesh and the devil, and our human nature, because of original sin, inclines us to choose evil esp. when it is disguised as good by the devil, who is the source of every lie, esp. the lie that disguises evil in the glamour of good. Abortion, killing an innocent baby, is cloaked as a good: choice. Eating killer foods is disguised as a good: flavor, taste, satisfaction. When the devil takes a need for something good which has been hard-wired into us by God, our Creator, and convinces us to try and fill that need with something other than what the Creator intended, that is a temptation.
The world tempts by substituting values of the world (pop culture, culture of death etc) for God’s will, expressed in the commandments and beatitutdes. The flesh tempts by substituting desire for good things: wholesome nutritious food, natural appetites that sustain the species and the family etc; for evil things: synthetic harmful foods, sex outside natural constraints and channels etc.
Our easy fall to temptation comes from our nature unaided by grace. By asking for and relying on grace we can resist temptation, and come to recognize the lies and choose the good, but only through grace, unaided we can do nothing.
