Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil. Hebrews 2:14 (NKJV)
Some Christians are afraid to talk about Satan or think about spiritual warfare. While we should be careful not to underestimate his destructive arsenal (Jude 9), we should never fear the devil.
Although he is still active by God’s permission, the devil has been soundly defeated. He is a rebellious angelic creature on the losing end of a cosmic struggle with Creator God. He knows his fate is the lake of fire from which he will never escape (Revelation 20:7-10).
At the cross, Jesus “disarmed the rulers and authorities [Satan and his demons]” and “made a public display of them, having triumphed over them through Him” (Colossians 2:15 NASB). Jesus defeated the devil at the cross by delivering you from sin’s penalty, death. Satan is a vanquished foe, and he knows it. You are no longer under his dominion but under the rule and reign of Christ.