Pope Francis highlights St. Peter's repentance on Holy Thursday

March 28 (UPI) -- Pope Francis praised priests as "heroic" witnesses but called on them to move closer to Christ through adversity such as shortcomings and "hardened hearts" during the Chrism Mass at the Vatican on Thursday.

Pope Francis was joined in St. Peter's Basilica for his Holy Thursday Mass by 42 cardinals, 42 bishops and 1,800 priests. The pope, who has faced several health challenges, arrived in a wheelchair. His homily ran for about 20 minutes.

Francis said hard times are opportunities to embrace Christ and meaningful ways. He reminded priests in his homily that St. Peter, the first pastor of the Catholic Church, denied Christ three times, leaving the apostle in tears.

He said St. Peter "rising up from his wounded heart, liberated him from his false notions and his self-assurance."

"Thank you, dear priest, for your open and docile hearts. Thank you for all your hard work and your tears. Thank you, because you bring the miracle of God's mercy to our brothers and sisters in today's world. May the Lord console you, strengthen you and reward you."

The pontiff said weeping in terms of feeling sorry for ourselves and weeping in recognition of our sins and coming closer to God are two different things and the latter is more cleansing of the soul.

"It does not mean weeping in self-pity, as we are so often tempted to do," Francis said. "[Weeping for ourselves] means seriously repenting for saddening God by our sins; recognizing that we always remain in God's debt, admitting that we have strayed from the path of holiness and fidelity to the love of the One who gave His life for us."

Pope Francis closed his homily with a prayer asking God to console, strengthen and reward the priests who have remained faithful to his word and teachings.

In February, doctors treated Pope Francis after his general audience for flu-like symptoms. Last November, doctors performed a CT scan that came back negative after he exhibited flu-like symptoms.

A year ago, Pope Francis batted acute bronchitis but managed to overcome it.