NEW : Pope says God 's ` ` patient fidelity is stronger than darkness and death '' Bishops will be held accountable for not protecting youths . Christmas service is expected to bring 11,000 faithful to the Vatican . Pope Francis personally chose a piece by Mozart for the Mass . Service began days after he sharply criticized the Vatican government .
NEW : Pope says God 's ` ` patient fidelity is stronger than darkness and death '' Christmas service is expected to bring 11,000 faithful to the Vatican . Pope Francis personally chose a piece by Mozart for the Mass . Service began days after he sharply criticized the Vatican government .