19We know that we are from God, and the whole world lies in the power of the evil one.
1 Peter 5:8 ESV
8Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour.
Why are humans inclined to sin? Why is it that some lust and commit adultery, others gossip and slander, yet others allow greed to lead them down a sinful path? Romans 5 is clear that when Adam sinned it affected us all.
Only God Can Protect Us from Evil
John 17:15 ESV
15I do not ask that you take them out of the world, but that you keep them from the evil one.