Christians should go out into the world to follow God but use "holy cunning" to guard against the snares of temptation, Pope Francis said.
The pope made the remarks at a Mass in St. Peter's Basilica on Monday on the feast of the Epiphany, which marks the manifestation of Jesus as savior to the world.
In his homily, the pope said that life is a journey, and like the three Wise Men, or Magi, people are looking for the "fullness of truth and of love which we Christians recognize in Jesus, the light of the world."
Jesus is found by reading the world of God's creation and the sacred Scripture, which nourishes the soul and "enables us to encounter the living Jesus, to experience him and his love," the pope said.
On life's journey, we need to be "attentive, alert and listen to God who speaks to us" and be prepared when we encounter "darkness, suspicion, fear and jealousy."
This happened to the Magi when they briefly lost sight of the star to Bethlehem and passed through Jerusalem where they encountered King Herod, who was "distrustful and preoccupied with the birth of a frail child whom he thought of as a rival," the pope said.
Jesus wasn't interested in usurping the king, "a wretched puppet," the pope said, but in overthrowing the devil.
Nonetheless, the king and his counselors felt threatened and feared "a whole world built on power, on success, on possession, on corruption was being thrown into crisis by a child," the pope said.
"The Magi were able to overcome that dangerous moment of darkness before Herod, because they believed in the Scriptures," and believed the Messiah would be born in Bethlehem, he said.
They were able to flee the darkness and resume their journey toward God because of a "holy cunning, that is, a spiritual shrewdness which enables us to recognize danger and to avoid it."
Pope Francis said Jesus' instruction to his disciples to "be wise as serpents and innocent as doves" means Christians must welcome God into their hearts and "cultivate that spiritual cunning which is able to combine simplicity with astuteness."
The Magi "teach us how not to fall into the snares of darkness and how to defend ourselves from the shadows which seek to envelop our life," the pope said.
Like the Magi, we need to "safeguard the faith with holy cunning, guard it from that darkness which, many times, is also disguised as light," he said.
"Shield it from the song of the Sirens," who seek to distract us from taking the right path, guarding one's faith "with prayer, with love, with charity."
The Magi also teach us "not to be content with a life of mediocrity, of playing it safe, but to let ourselves be attracted always by what is good, true and beautiful -- by God," he said.
Look to the heavens as they did, aim high and "follow the great desires of our heart" while also being wise to the deception of appearances, by what the "world considers great, wise and powerful."
"We must not be content with appearances," but press on, past the darkness and worldly temptations, to the periphery, to Bethlehem, to find the true light and king of the universe, the pope said.
After the Mass, tens of thousands of people streamed to St. Peter's Square to listen to the pope's noon prayer and to visit the Vatican's Nativity scene.
Like the star that appeared in the night sky over Bethlehem, God is the first to appear and signal to the world his presence, the pope said.
God is always the first to take the initiative -- he is the one who invites and then patiently waits.
"The Lord calls you, the Lord looks for you, the Lord waits for you," the pope said. "The Lord doesn't proselytize. He gives love and this love looks for you and waits for you, you! Even if right now you don't believe or you are far" from God.
The pope noted Monday marked World Day of Missionary Childhood, and he praised the efforts by Christian children to spread the Gospel and reach out to the less fortunate.
The pope also extended a Christmas greeting to Eastern Christians who follow the Julian calendar and were preparing to celebrate the birth of Christ on Tuesday.
He asked that Jesus "strengthen in everyone their faith, hope and love, and give comfort to the Christian communities experiencing ordeals."