Because He is gracious, God saves us on the basis of faith in His Son.  Then He gives us a new nature empowered by the Holy Spirit who comes to live within each Christian.

From 1 Peter 1:3-5:  “Blessed be the God and Father of our Lord Jesus Christ!  By His great mercy He has given us a new birth into a living hope through the resurrection of Jesus Christ from the dead and into an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you, who are being protected by the power of God through faith for a salvation ready to be revealed in the last time.”