To unite your physical lives, your material interests, to become partners in order to face together the difficulties and successes, the defeats and victories of life—that is the very foundation of marriage, but you already know that it is not enough.
To be united in your sensations, to have the same aesthetic tastes and enjoyments, to be moved in common by the same things, one through the other and one for the other—that is good, that is necessary, but it is not enough.
To be one in your deeper feelings, to keep a mutual affection and tenderness that never vary in spite of all the blows of life and can withstand every weariness and irritation and disappointment, to be always and on every occasion happy, extremely happy, to be together, to find in every circumstance tranquillity, peace and joy in each other—that is good, that is very good, that is indispensable, but it is not enough.
To unite your minds, to harmonise your thoughts and make them complementary, to share your intellectual preoccupations and discoveries; in short, to make your sphere of mental activity identical through a widening and enrichment acquired by both at once—that is good, that is absolutely necessary, but it is not enough.
Beyond all that, in the depths, at the centre, at the summit of the being, there is a Supreme Truth of being, an Eternal Light, independent of all the circumstances of birth, country, environment, education; That is the origin, cause and master of our spiritual development; it is That which gives a permanent direction to our lives; it is That which determines our destinies; it is in the consciousness of That that you must unite. To be one in aspiration and ascension, to move forward at the same pace on the same spiritual path, that is the secret of a lasting union.
– The Mother (CWM, Vol.13, pp.236-237)