Matthew 6:13 in the Lord's prayer Jesus taught us to pray: "lead us not into temptation, but deliver us from evil." (Many of the translations of scripture render this phrase: deliver us from the Evil One.) This refers, of course, to Satan or the Devil. The Christian's conflict is with the enemy of our soul, Satan.
Peter writes about our adversary in 1 Peter 5:8, "Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour."
Notice, however, that Peter says "may" not "can" devour. English grammar teaches that "may" means to give permission, whereas "can" means having the ability. Thus, for Satan to devour us we must give him permission. As children of God, he cannot harm us without permission, for Jesus has redeemed us from his power at Calvary!
We have a choice to whom we give permission to influence us, to whom we yield our lives. 1st John 4:4 tells us, "Greater is He that is in you, than he who is in the world." Choose to yield to (obey) God! James 4:7 says, "Submit yourself therefore to God. Resist the devil and he will flee from you." Let the devil know that Jesus is who you choose to obey! Jesus overcame Satan's temptations. So can we, with His help!