Pope Francis urged Catholics to cling to Christ and pray for the courage to say "yes" to God in his call for vocations. Acknowledging that discerning God's plan is a daunting task, the pope said that trust in the Lord can overcome our fears.

"When we are called to leave safe shores and embrace a state of life – like marriage, ministerial priesthood, consecrated life – our first reaction is often … disbelief. Surely, this vocation is not for me! Can this really be the right path? Is the Lord really asking me to do this?" Pope Francis said in his message for this year's World Day of Prayer for Vocations.

The pope said that Christ knows all of the "questions, doubts and difficulties that toss the boat of our heart" and said it is important to remember that the Lord is always present, "ever at our side even amid stormy seas" with the reassurance: "'Take heart, it is I; have no fear.'"

"Every vocation brings with it a responsibility," he said. "The Lord calls us because he wants to enable us, like Peter, to 'walk on water', in other words, to take charge of our lives and place them at the service of the Gospel, in the concrete and everyday ways that he shows us, and specifically in the different forms of lay, priestly and consecrated vocation."

Pope Francis pointed to Mary's courageous "yes" to God at the Annunciation as a model to follow:

"Cultivate the interior disposition of the Blessed Virgin Mary. Grateful that Lord gazed upon her, faithful amid fear and turmoil, she courageously embraced her vocation and made of her life an eternal song of praise to the Lord."

"Every vocation is born of that gaze of love with which the Lord came to meet us," he said. "We will succeed in discovering and embracing our vocation once we open our hearts in gratitude and perceive the passage of God in our lives."

The pope stressed that vocational discernment is not simply "a decision we make as isolated individuals."

"Vocation, more than our own choice, is a response to the Lord's unmerited call," he said.

Pope Francis' message was released this week in advance of the 57th World Day of Prayer for Vocations, which will be celebrated on May 3. This year's theme is "Words of Vocation."

These "words of vocation" are gratitude, encouragement, and praise, the pope said. Gratitude for the gift of one's vocation, awareness of Christ's presence and encouragement as one follows God's will, and perseverance and praise, "even amid storm-tossed waters."

Pope Francis asked the Church to continue to promote vocations:

"May she touch the hearts of the faithful and enable each of them to discover with gratitude God's call in their lives, to find courage to say 'yes' to God, to overcome all weariness through faith in Christ, and to make of their lives a song of praise for God, for their brothers and sisters, and for the whole world."