Jessie Penn-Lewis explores the distinction between the soul and spirit as described in Hebrews 4:12, emphasizing that the Word of God penetrates deeply into the human being, discerning the spiritual from the carnal. She explains that the soul represents the lower, animal desires shared with beasts, while the spirit connects us to God and the divine. The sermon highlights the importance of understanding this distinction for spiritual growth, as the spirit should govern the soul and body, rather than being subservient to them. Penn-Lewis also discusses the implications of being 'natural' or 'carnal' and the necessity of the Holy Spirit for true spiritual life. Ultimately, she calls for a recognition of the spiritual realities that transcend mere soulish experiences.