§1604

God who created man out of love also calls him to love the fundamental and innate vocation of every human being. For man is created in the image and likeness of God who is himself love. Since God created him man and woman, their mutual love becomes an image of the absolute and unfailing love with which God loves man. It is good, very good, in the Creator's eyes. And this love which God blesses is intended to be fruitful and to be realized in the common work of watching over creation: "and God blessed them, and God said to them: 'Be fruitful and multiply, and fill the earth and subdue it.'"