“Finally, be strong in the Lord and in the strength of His might. Put on the full armor of God, so that you will be able to stand firm against the schemes of the devil. For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places. Therefore, take up the full armor of God, so that you will be able to resist in the evil day, and having done everything, to stand firm.”
Ephesians 6:10-13 NASB
You can be easily distracted and sucked into thinking like the world thinks as we are continually being bombarded with thoughts of greed, anger, lust and cynicism. This generally does not happen all at once but it can sneak up on you. You simply cannot afford to let your guard down. You need at all times to be alert and have the full armor of God on protecting your mind, knowing that He who is in you is greater than he who is in the world. And if God be for you, who can be against you?
Here is an exercise that will help: read Colossians 3 and meditate on it.