Purity of heart means having a single eye for God alone. As a result, we can perceive God, who is Spirit, and become illumined with him who is light. However, we need to realize that the material world is opposed to the spiritual world. We have to make a choice. Fr. Bertrand shows us what we must do to understand the beatitude, “Blessed are the clean of heart for they shall see God” (Mt 5:8).