Our spirits are sanctified upon regeneration. As long as we are obedient to the Spirit, we will remain holy. But the soul must also become sanctified in it's essence. And that is the process of sanctification...dying daily and walking in obedience to God in the Spirit. So we must continually CHOOSE holiness over our old lives. Jesus said we must overcome! Jesus starts us out and equips us, but we are the ones building through our wills. So we can build with carnal materials or with holy ones...and we are then judged on how we have built whether we are to be honoured or dishonoured.