Mutual submission.  Humbling of the self outwardly and inwardly - by deeds and by attitude.  This creates beauty.  This is a form, always, of suffering - of dieing; dieing to self.  This also creates love, nutures it, gives it increase.  On this form of love you can build oneness of heart.  It creates productivity in work, intimacy in marriage, unity in the society of families, villages, cities and nations.  Mutual submission in lovers creates an intense bond; image of the Trinity, of Incarnation.  The summa of Mystery.