Spiritual warfare is a strong term used to describe a frighteningly powerful concept. Human beings are locked in a life and death struggle with spiritual forces that are both external and internal.

Externally, there is Satan and his fallen angels, tempting us, pushing us to rebel against God. The world itself, fallen as it is, tempts us to abandon God for temporal pleasures. Internally, our own sin-sick hearts produce lusts and longings which, if undisciplined, will lead us away from God. Together, these three enemies
(the world, the flesh, and

the Devil)
Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come
Ephesians 1:21