Do not be conquered by evil, but conquer evil with good.
In verse 1, the exhortation is to become a lining sacrifice and I wanted to meditate on that, but verse 21 distills it perfectly. I think the end goal of the message of being a living sacrifice is exactly this: to conquer evil with good. Messiah conquered evil with good. We are to be his disciples, we are to follow after him, walking the same path of righteousness and loving kindness. He made himself a sacrifice and yet lives. We are called to be living people who are sacrifices, we are to be set apart, dedicated to the work of the Kingdom. In so doing, we will be continually transformed. Rather we will continue to transform ourselves through Heavenly grace and blessing as we draw ever closer to the Father through study, prayer and action.
Walking In Liberty 