422. (xviii) Love, purified by wisdom in the understanding, becomes spiritual and celestial. Man is born natural, but as the understanding is elevated into the light of heaven and with it love is elevated into the heat of heaven, so he becomes spiritual and celestial; he then becomes like a Garden of Eden which has at once the light and heat of perpetual spring. It is not the understanding that becomes spiritual and celestial, but love; and when love becomes spiritual, it also makes its partner, the understanding, spiritual and celestial. Love becomes spiritual and celestial by a life in accordance with the truths which wisdom teaches and impresses. Love imbibes these truths by means of its understanding and not from itself; for love cannot be elevated except by knowing truths, and it can know these only by means of an elevated and enlightened understanding; and then as far as it loves truths by doing them, so far it is elevated. For it is one thing to understand, and another to will; or one thing to talk and another to do. There are those who understand and speak truths of wisdom, yet neither will them nor practise them. When, therefore, love does put into practice the truths of light, which it understands and talks about, it is elevated. That it is so, man may see from reason alone; for what can be said of the man who understands the truths of wisdom and speaks about them while he lives contrary to them, that is, while his will and conduct are opposed to them? Love purified by wisdom becomes spiritual and celestial, because man has three degrees of life, called natural, spiritual, and celestial, treated of in the Third Part of this work. Man can be elevated from one to another; yet he is not raised by wisdom alone, but by life in accordance therewith, for man's life is his love. Wherefore, he loves wisdom to the extent that he lives it; and that is the measure of his purification from what is unclean, that is from sins; and so far as he purifies himself, he loves wisdom.