The reason is that chastity is the removal of unchastity. It is a universal rule that so far as anyone removes evil, so far does good have a chance to replace it; and further, so far as evil is hated, so far is good loved, and vice versa. Consequently so far as promiscuity is banished, so far does the chastity of marriage come in. Anyone can see from what is generally felt, as soon as the statement is made and heard without waiting for proofs, that conjugial love is purified and corrected in so far as promiscuity is banished. But since what is generally felt is not felt by everyone, it is worth adducing proofs by way of illustration.

Conjugial love grows cold as soon as it is divided, and this chill is the death of it, for the warmth of an unchaste love quenches it. Two kinds of warmth of opposite types cannot exist together, without one banishing the other and depriving it of its power. So when the warmth of conjugial love removes and banishes the warmth of scortatory love, conjugial love begins to grow delightfully warm, and the feeling of delight makes it bud and flower, like an orchard or a rose-garden in springtime. This is the effect of the mixing in spring of heat and light from the sun of the natural world. But the other is the effect of the mixing in spring of heat and light from the sun of the spiritual world.