This is the victory that has overcome the world, even our faith. Who is it that overcomes the world? Only he who believes that Jesus is the Son of God. 1 John 5: 4b-5 (New International Version)
Sin kept humanity in a constant state of despair, even if we did not realized our plight. The Law appeared to present a remedy through the various offerings and sacrifices prescribed. However, these had been twisted by human reason so that they only fulfilled the desires of our heart, rather than appeasing the divine wrath that came as a result of sin. It was an ever-faithful God to offer to us the restoration to the relationship lost by sin.
This new life is a result of one human activity--faith. It is only when we see God revealed in Jesus the Messiah Lord that we can be "saved" from sin. There are no amount of good works that we can accomplish that will satisfy God's anger toward sin. There are no amount of acts of piety that will bring us into God's favor. The victory we have over sin and death come because of what the Father accomplished through the Son at Calvary.
This is the Gospel we need to share in the 21st century world. Faith has been defined by our Lord, not by the human heart. Salvation is about embracing the One who died on behalf of our sins as both Lord and Savior. This relativistic world desires salvation just to be given, with no strings. However, God demands the same obedience that He has always expected from His people. Like Abraham, we must "believe in God, so that it might be reckoned to us as righteousness."