How do we know we have overcome the devil?

According to 1 John 2:13, believers can be assured that they have overcome the wicked one, not through their own strength but through their union with Christ who has defeated sin and Satan. This assurance comes from understanding that Christ's work on the cross has secured victory over evil. As Revelation 12:10 elaborates, the accuser of the brethren has been cast down because of the blood of the Lamb. Believers live in the reality that they are more than conquerors through Him who loved them, encouraging them to share the gospel and engage in spiritual warfare confidently.