Warning that "every threat to the family is a threat to society itself," Pope Francis called on the people of the Philippines to be a prophetic witness in a world facing attacks on marriage and life.

"The family is also threatened by growing efforts on the part of some to redefine the very institution of marriage, by relativism, by the culture of the ephemeral, by a lack of openness to life," warned Pope Francis, speaking Friday to families gathered at the Mall of Asia Arena in Manila during his Jan. 15-19 visit to the Philippines.

His comments on the threats to family come in the wake of Philippines president Benigno Aquino's signing a highly controversial reproductive health bill in 2013 that drew strong protest from local bishops and members of the faith.

The legislation requires government-sanctioned sex education for adults, middle school and high school students, as well as a population control program that includes fully subsidized contraceptives under government health insurance.

Pointing to numerous obstacles facing the Philippines and greater society, the Pope highlighted the need for "good and strong families to overcome these threats."

"God calls upon us to recognize the dangers threatening our own families and to protect them from harm," he said, emphasizing the importance of living out the vocation of family.

"Be sanctuaries of respect for life, proclaiming the sacredness of every human life from conception to natural death," he urged.

Huge crowds have turned out for the Pope's Masses and public events in the Philippines, where 86 percent of the population identifies as Catholic. In recent years, the island country has struggled with the effects of several typhoons, earthquakes and other natural disasters.

In his address, Pope Francis first noted the importance of resting in the Lord. He observed that God revealed his will to St. Joseph through dreams as he slept.

"In this moment of rest in the Lord, as we pause from our many daily obligations and activities, God is also speaking to us. He speaks to us in the reading we have just heard, in our prayer and witness, and in the quiet of our hearts."

Resting is important not only for physical and mental health, but for spiritual health, the pontiff said, so that we can hear God's voice and understand his will for our lives.

Pope Francis encouraged those present to spend time in prayer every day. Weighed down by the burden of daily work and chores, he said, we must remember that if we do not make time for prayer, we will lose sight of God's will for our lives.

"And for all our activity, our busy-ness, without prayer we will accomplish very little."

Resting in prayer is particularly necessary for families, he added, because family is where we learn to know God and be part of his Church, and to love, forgive and be virtuous.  

"That is why families are so important in God's plan for the Church!" he said, calling on the nation to see families as "your country's greatest treasure."

Once we have heard God's voice, Pope Francis continued, we must rise from our sleep and act. He stressed the need for "holy and loving families to protect the beauty and truth of the family in God's plan and to be a support and example for other families."

"The pressures on family life today are many," Pope Francis acknowledged, pointing to the continued effects of natural disasters, economic difficulties, unemployment and migration.

"While all too many people live in dire poverty, others are caught up in materialism and lifestyles which are destructive of family life and the most basic demands of Christian morality," he said.

In response to these numerous challenges, he stressed, we have a "Christian duty to be prophetic voices in the midst of our communities."

"When families bring children into the world, train them in faith and sound values, and teach them to contribute to society, they become a blessing in our world," he said. "God's love becomes present and active by the way we love and by the good works that we do."

Noting that the Filipino bishops have called a Year of the Poor, the Holy Father also asked families to care for those who are in need, and "especially to show concern for those who do not have a family of their own, in particular those who are elderly and children without parents."

"Never let them feel isolated, alone and abandoned, but help them to know that God has not forgotten them," he said. "You may be poor yourselves in material ways, but you have an abundance of gifts to offer when you offer Christ and the community of his Church. Do not hide your faith, do not hide Jesus, but carry him into the world and offer the witness of your family life!"