Ephesians 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.

Often, we think we are wrestling against other people or against challenges at work, at home, in the church, or in the culture.  We think that we are just trying to get a job done or to win an argument.  That isn't the case at all.  There is a spiritual battle going on, and winning it is vital.