A Living Sacrifice
12 Therefore, I urge you, brothers and sisters, in view of God’s mercy, to offer your bodies as a living sacrifice, holy and pleasing to God—this is your true and proper worship. 2 Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is—his good, pleasing and perfect will.
Humble Service in the Body of Christ3 For by the grace given me I say to every one of you: Do not think of yourself more highly than you ought, but rather think of yourself with sober judgment, in accordance with the faith God has distributed to each of you. NIV Bible Gateway.com
By placing faith in Jesus Christ, a person becomes a new believer and is sanctified - that is, set apart for God's purposes. Unlike salvation, which takes place in a single moment, sanctification is a lifelong process. We who are followers of the Savior should be letting the Holy Spirit control our lives. If that's the case, we are currently being sanctified, regardless of what we may feel or how our actions appear to those around us. In other words, we are progressively maturing in our faith.
And if we are progressing, we must be working our way toward something. The apostle Paul explained the Christian's mission: "For those whom [God] foreknew, He also predestined to become conformed to the image of His Son" (Rom. 8:29). A believer's character, conduct, and conversation should be reflections of Jesus, who lives within. On our own, we might place too much emphasis on behavior and get caugh up in following rules and rituals that look Christian without truly reflecing Christ. But God has given each believer His Holy Spirit as a teacher and guide. The Spirit works to transform our minds and hearts so that we are markedly different from our unsaved peers. When we allow the Spirit to control us, we speak and act in acordance with our true identity: God's sons and daughters.
Our Father wants His children to be living examples of who He is. He doesn't expect perfection - He knows we can't be totally sinless in our human body. But He shows us how to think and act so we may "walk in a manner worthy of the calling with which [we] have been called" (Eph. 4:1).
Stanley, Charles F. "Set Apart for God." In Touch: Daily Readings For Devoted Living August 2016. Atlanta: In Touch Ministries. page 30.