"Marriage is a symbol of life... the Sacrament of love of Christ and the Church, a love which finds its proof and guarantee in the Cross."

This was the central theme of Pope Francis' homily for the feast of the Exaltation of the Cross, delivered moments before presiding over the marriages of 20 couples from the Diocese of Rome.

The weddings, which took place in Saint Peter's Basilica on Sunday morning in the presence of family and loved ones, come just weeks before the Synod on the Family is set to begin in the Vatican.

"The love of Christ, which has blessed and sanctified the union of husband and wife," the Pope said in his homily, "is able to sustain their love and to renew it when, humanly speaking, it becomes lost, wounded or worn out. The love of Christ can restore to spouses the joy of journeying together."

Marriage, he continued, is about  "man and woman walking together, wherein the husband helps his wife to become ever more a woman, and wherein the woman has the task of helping her husband to become ever more a man.

"Here we see the reciprocity of differences," he said.

The path is not always smooth for married couples, the Pope continued, nor is it "free of disagreements." If it were, "it would not be human." Rather, "it is a demanding journey, at times difficult, and at times turbulent, but such is life!"

Turning to the first reading taken from the book of Genesis, the Holy Father reflected on those who followed Moses through the desert, in the same way the Church "makes her way across the desert of the contemporary world, the People of God composed, for the most part, of families."

"It is impossible to quantify the strength and depth of humanity contained in a family," he said, as demonstrated through the "mutual help, educational support, relationships developing as family members mature, the sharing of joys and difficulties."

"Families are the first place in which we are formed as persons and, at the same time, the 'bricks' for the building up of society."

The Holy Father recalled how the people in the desert were tempted to turn back, having become impatient amid the hardships of the journey.

Like those depicted in the reading, the Pope said that married couples may also "become impatient on the way," as the "hardship of the journey causes them to experience interior weariness; they lose the flavor of matrimony and they cease to draw water from the well of the Sacrament. Daily life becomes burdensome, even 'nauseating'."

Pope Francis recalled how many of those in the desert, "during such moments of disorientation," died after being bitten by poisonous serpents, leading the people to repent.

Rather than destroying the serpents, however, God provided an "antidote": "by means of the bronze serpent fashioned by Moses," he said, "God transmits his healing strength, his mercy, which is more potent than the Tempter's poison."

In the Gospel reading, the Pope said, "Jesus identifies himself with this symbol" of the bronze serpent. It was through the Father's "immense love," he said, that the Son became man, "to become a servant and to die for us upon a cross. Out of such love, the Father raises up his son, giving him dominion over the entire universe."

"Whoever entrusts himself to Jesus crucified receives the mercy of God and finds healing from the deadly poison of sin," he said.

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This cure applies in a particular way to spouses, like the followers of Moses, they "have become impatient on the way," succumbing to temptation to "discouragement, infidelity, weakness, abandonment."

If married couples entrust themselves to Jesus, who has come not to condemn but to save them, he "will bring them healing by the merciful love which pours forth from the Cross, with the strength of his grace that renews and sets married couples and families once again on the right path."