 John Paul II continued on the Catholic theology of the body of his predecessors with a series of lectures, entitled the Theology of the Body, in which he talked about an "original unity between man and women", purity of heart (on the Sermon on the Mount), marriage and celibacy and reflections on "Humane Vitae", focusing largely on responsible parenthood and marital chastity.He links "the original unity of man and women" with the book of Genesis, and raises in this context questions such as why Christ put so much emphasis on human beings as male and female.He argues, Man becomes the Image of God in the moment of holy communion.