"How beautiful, then, the marriage of two Christians, two who are one in hope, one in desire, one in the way of life they follow, one in the religion they practice. They are as brother and sister, both servants of the same Master. Nothing divides them, either in flesh or in spirit. They are, in very truth, two in one flesh; and where there is but one flesh there is also but one spirit.
They pray together, they worship together, they fast together; instructing one another, encouraging one another, strengthening one another. Side by side they visit God's church and partake of God's Banquet; side by side they face difficulties and persecution, share their consolations. They have no secrets from one another; they never shun each other's company; they never bring sorrow to each other's hearts.
Unembarrassed they visit the sick and assist the needy. They give alms without anxiety; they attend the Sacrifice without difficulty; they perform their daily exercises of piety without hindrance. They need not be furtive about making the Sign of the Cross, nor timorous in greeting the brethren, nor silent in asking a blessing of God. Psalms and hymns they sing to one another, striving to see which one of them will chant more beautifully the praises of their Lord. Hearing and seeing this, Christ rejoices. To such as these He gives His peace. Where there are two together, there also He is present; and where He is, there evil is not."
(Tertullian, Letter to His Wife, ca. 202 A.D.)The unitive nature of the marital bond brings about its procreative nature in the fullest sense. A couple's fruitfulness is not based on its biological fecundity, but on their sacramental unity. A husband and wife stand before God as one on their wedding day, and henceforth they must come to God as one in their prayer, in their sacrifice, in their works of mercy. Their strength as a couple will ever increase or continually diminish, as they strive for this unity or deviate from the path towards it.
The devil is fully aware of the powerful strength of this bond and so constantly seeks to divide and conquer each spouse on his own. His ways are so cunning and his deceit so subtle that he easily introduces friction into a marriage. He encourages spouses to lead separate lives, if not in deed than in thought; ones that are parallel but never intersecting.
Yet this is where our faith is so very vital to the wellbeing of marriages. God has not only given couples abundant graces, but also abundant opportunity to grow in virtue as a couple together. Family life offers ample opportunities for a couple to approach our Lord together through prayer, works and sacrifice. These three things done together lead to an interior unity which is much greater and more fruitful than a physical one. For we witness from the supernatural unions of the saints with Christ and His Church, that much fruit comes from a marriage that is free from any impediments, any tangential distractions. The great harvest of souls that the saints produced is witness to the great unity of hearts that was theirs: their heart and His Most Sacred Heart.
How truly tremendous is the vocation of Christian matrimony! How many more souls can be brought into His kingdom by the fruitful union of the spouses: the souls of children, but just as importantly, the souls of the spouses.