Do not destroy the principle of life within you

“Those who have taken upon themselves the responsibility of wedded life should see to it that they do not abuse the course of nature; that they do not destroy the principle of life within them, nor violate any of the commandments of God. The command which he gave in the beginning to multiply and replenish the earth is still in force upon the children of men. Possibly no greater sin could be committed by the people who have embraced this gospel than to prevent or to destroy life in the manner indicated. We are born into the world that we may have life, and we live that we may have a fulness of joy, and if we will obtain a fulness of joy, we must obey the law of our creation and the law by which we may obtain the consummation of our righteous hopes and desires-life eternal” (Joseph F. Smith, We Believe, under Family and Parenthood, 206).