The Soul of the Apostolate emphasizes that true apostolic work must be rooted in a deep inner life and dependence on God, not merely in human activity or excessive 'activism.' The book emphasizes the importance of receiving God's gifts to share with others, and aligning all activities with the will and power of Christ to achieve true results. By deepening the spirituality of the inner life, everyday work can be elevated to a supernatural level, according to Jean-Baptiste Chautard's book of spirituality and practical advice.