This work by St. John of Damascus elaborates on the theological understanding of the body and blood of Christ as partaken by believers. It emphasizes that Christ, having taken on human flesh from the Virgin Mary, offered a singular and eternal sacrifice for humanity's sins. The text also draws parallels between the natural growth of the human body and the spiritual growth of believers as members of Christ's body through the Eucharist. It presents the idea that, although Christ's body was corruptible before His resurrection, through His divine power, it became incorruptible, allowing believers to partake in His divine nature.