Christians today need a new way of thinking about the world around them. They need an optimistic, more positive way of thinking in regards to engaging the culture.
This new way of thinking is about victory in the life of a regenerate believer, over his or her indwelling sin, and it doesn't just stop with individual sanctification but flows outward into every area of life. Victory not only includes individual sanctification, but it also means societal sanctification. We won't ever be perfectly victorious over sin or its effects, at least not until you die or until the resurrection takes place. This does not mean however that God allows us to stay in our sin. No, God progressively sanctifies his people and reverses the effects of sin in a believer's life and this sanctification flows out and affects society. Society should mirror individual sanctification. Victory is progressive over sin's effects in society. This is what Deuteronomy 8 and 28:1-14 teaches.
I'm not talking about perfectionism or sinless perfection, but the progression of victory over sin and its effects for the individual and society. After the 1870's this optimistic view about society digressed into a pessimistic view of the world. Social sanctification was rejected and replaced with "a vision of defeat, in time and on earth . . . and churches went into hiding, culturally speaking" .
For those who may not have a clear definition of personal or individual sanctification, this simply means that someone who is born-again, progressively conforms their life to biblical standards for ethics. Another way of putting it is being conformed to the image of Christ, that is to say the perfect humanity of Christ. We don't conform to God's divine nature because men do not evolve into God as the Mormons teach. We conform to God's standards as manifested in Christ. Sanctification is a progressive process of God separating yourself from sin (as defined by God's law), not perfectly, but increasingly, in time and on earth.
Social sanctification mirrors personal sanctification. When Christians structure their lives in accordance with what the Bible requires, the world around them begins to reflect that change. It's really a simple concept. Jesus said, "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you” . The effects of the Gospel flow from Christian living. The gospel has a leavening effect like yeast in dough. The gospel lived out through God's people progressively sanctifies society--setting society apart for God's glory just as God does for the individual and just as He did for Israel in the Old Covenant.
Until the knowledge of the LORD covers the earth as the waters cover the seas,
 "Backward, Christian Soldiers?" Gary North
 (Matthew 28:19-20 ESV)