"for sinful relationships with another person's spouse." In Theology of the Body, a series of lectures given by Pope John Paul II, Jesus' statement in Matthew 5:28 is interpreted that one can commit adultery in the heart not only with another's spouse, but also with his/her own spouse if one looks at him/her lustfully or treats him/her "only as an object to satisfy instinct". Purity of heart is suggested as the necessary quality needed to accomplish this task; common Catholic prayers and hymns include a request for this virtue. The Church identifies gifts of God that help a person maintain purity: Chastity, which enables people to love others with upright and undivided hearts. Purity of intention, which seeks to fulfill God's will in everything, knowing that it alone will lead to the true end of man. Purity of vision, "external and internal", disciplining the thoughts and imagination to reject those that are impure. Prayer that recognizes the power of God to grant a person the ability to overcome sexual desires. Modesty, of the feelings as well as the body is discreet in choice of words and clothing. Jesus stated, "Blessed are the clean of heart, for they shall see God." This purity of heart, which the ninth commandment introduces, is the "precondition of the vision of God" and allows the person to see situations and people as God sees. The Catechism teaches that "there is a connection between purity of heart, of body and of faith." Tenth commandment Detachment from riches is the goal of the tenth commandment and the first Beatitude ("blessed are the poor in spirit") because, according to the Catechism, this precept is necessary for entrance into the Kingdom of heaven. Covetousness is prohibited by the tenth commandment because it is considered to be the first step toward commission of theft, robbery and fraud; these lead to violence and injustice. The Church defines covetousness as a "disordered desire" that can take different forms: Greed is the desire for too much of what one does not need. Envy is the desire for what belongs to another. The US Bishops define it as "an attitude that fills us with sadness at the sight of another's prosperity." Explaining Church teaching of this commandment, Kreeft cites Saint Thomas Aquinas, who wrote, "An evil desire can only be overcome by a stronger good desire." The US Bishops suggest that this can be