20When you were slaves of sin, you were free in regard to righteousness.21So what advantage did you then get from the things of which you now are ashamed? The end of those things is death. 22But now that you have been freed from sin and enslaved to God, the advantage you get is sanctification. The end is eternal life. 23For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord. (Romans 6:20-23, NRSV)
When we are slaves to God and follow the life that God has planned for us, we are free from sin and death and the gift that we get is eternal life.
This is all because of Jesus and God and nothing we can boast in.
But the advantage of being a slave of God is eternal life.
We are gifted life and freed to live eternally with God!