I pray that, according to the riches of his glory, he may grant that you may be strengthened in your inner being with power through his Spirit and that Christ may dwell in your hearts through faith, as you are being rooted and grounded in love. I pray that you may have the power to comprehend, with all the saints, what is the breadth and length and height and depth. – Ephesians 3:16-18 (NRSVUE)
The primary work of the Holy Spirit in the life of a believer, Martin Luther tells us, is to inspire faith. Faith is not so much a matter of knowledge of Christ as it is a complete trust and dependence on Christ. That is, on our own we attempt to be good enough to earn our salvation. Yet, these attempts are ways of trusting our own abilities rather than placing our full trust in God. It is only when we despair of our ability to earn our salvation that the Holy Spirit enters our hearts and inspires us to place our trust not in ourselves but rather in Christ. When this occurs, we are justified, or made right with God. Salvation comes to us in this process where our trust is shifted from our own abilities and action to trust in the grace made known in Christ, and it is a process made possible by the Holy Spirit at work in our hearts.
Luther says that each of us has both an outer self or person and an inner self or person. Luther contends that the inner person is renewed daily by the work of the Holy Spirit, even as the outer person wastes away. The outer person is the old sinful Adam, marred by sin and helplessly self-centered. A life centered on the self is dominated by fear and anxiety as one struggles to prove oneself worthy in a world full of dangers and adversity. Yet when the Holy Spirit comes to a person, it forms a new creation in the person’s heart. This new creation is an aspect of the continually transforming creativity of the Holy Spirit and the Word of God. It is new every day. The inner person is full of hope and joy. Because it is renewed daily, this inner person grows stronger over time.
The outer person is a reflection of one’s inner thoughts and feelings. As hope and joy replace fear and anxiety, the outer person is slowly transformed to reflect the new creation of the inner person. This process is never complete and is not linear, but the transformation nonetheless occurs. This transformation is not one’s own work but is a gift of the Holy Spirit. We call this ongoing process of renewal “sanctification” or “being made holy.” To be holy is not something we can achieve on our own or even notice in ourselves, but is rather the slow working of the Holy Spirit in our hearts.