1 Corinthians 15:57
But thanks be to God! He gives us the victory through our Lord Jesus Christ.
There are two ways that we can look at our spiritual life. One way is a day to day struggle with sin where we lose some battles and fall into temptation but resist at other times. The other way is that the victory is already won because Jesus has paid the penalty for our sins and we have been forgiven.
Both of these views are accurate depending on perspective. Our victory over sin is totally secure because Jesus has conquered sin and death. 1 Corinthians 15 is all about the resurrection of Christ and what that means to us as Christians.
So our salvation is secure and when our faith is in Jesus nothing can take away that eternal victory. But our daily walk is still a struggle. We must battle temptation every day. This is where we have more victory in Jesus however.
Because we have been given the Holy Spirit, we have the ability to resist sin. The Holy Spirit helps us recall the teachings of Jesus and prompts us when we must make decisions between right and wrong.
In the war of sin, we are already victorious on account of the work of Jesus. We can also be victorious in our daily battles thanks to the Holy Spirit and the teachings of Jesus.