"Submit yourselves, then, to God. Resist the devil, and he will flee from you." James 4:7
C.S. Lewis once wrote, "There are two equal and opposite errors into which our race can fall about the devils (demons). One is to disbelieve in their existence. The other is to believe and to feel an excessive and unhealthy interest in them."
Lewis's point is that the Christian must walk the fine line between being certain that Satan is real and being so fixated on him that our eyes cease to be fixed on Jesus.
If we err in the first regard, then we will never be ready and armored up when the true attacks of the enemy come.
If we err in the second regard, we will spend so much of our time hunting for the work of the devil that we will fail to embrace the work of God.
This is the daily responsibility of the Christian:
We are to take up our cross and follow Jesus daily.
When we submit ourselves willingly to God, we are given the power to resist the fiery darts of the enemy that come our way. And because of that resistance, the devil will flee from us.
But how do we resist the work of the devil?
For that answer, we turn to the example of Jesus:
The devil led him to Jerusalem and had him stand on the highest point of the temple. "If you are the Son of God," he said, "throw yourself down from here. For it is written: "'He will command his angels concerning you to guard you carefully; they will lift you up in their hands so that you will not strike your foot against a stone.'" Jesus answered, "It is said: 'Do not put the Lord your God to the test.'" When the devil had finished all this tempting, he left him until an opportune time (Luke 4:9-13).
When we face temptation, it will come in a variety of ways. The devil might appeal to our physical desires; he might appeal to our pride and sense of self; he might appeal to our faith and whether God is who He says He is and will do what He says He will do.
How will we stand up against that kind of temptation?
We can only do so when we have had our minds regularly fixed on the Word of God. By doing so, we will know the lie from the truth, even when that lie is subtle.
So, the surest way to resist the devil?
It's with the Word of God.