During his homily at daily Mass in the Vatican's Saint Martha House, Pope Francis said Christians must have the courage to flee from the temptation to sin by turning to the Lord when they are weak.

"We are weak, but we must be courageous in our weakness. And often our courage must be expressed in escaping without looking back, so as not to fall into the trap of wicked nostalgia," preached the Bishop of Rome July 2.

"Do not be afraid, and always look to the Lord," he added.

The Mass was concelebrated by Cardinal Manuel Montiero de Castro, major penitentiary of the Apostolic Penitentiary, and by Archbishop Beniamino Stella, president of the Pontifical Ecclesiastical Academy. It was attended by priests and employees of the two offices.

Pope Francis was reflecting on Lot's escape from Sodom, recounted in the first reading at the Mass. An angel urged Lot to flee, but he was slow to do so, carrying within himself an "inability to detach himself from evil and sin."

Even when we wish to flee, there can be "something that pulls us back," said Pope Francis. "It's so hard to cut ties with a sinful situation. It is hard," he affirmed.

The Roman Pontiff added, however, that "the voice of God tells us this word: 'Escape! You cannot fight there, because the fire, the sulfur will kill you. Escape!'"

He noted St. Therese of Lisieux, who said that "in some temptations, the only solution is to escape, to not be ashamed to escape, to recognize that we are weak and we have to escape."

Pope Francis added that there is wisdom in the epigram "he who fights and runs away, lives to fight another day."

Escape, he said, "to go forward along the path of Jesus."

Lot was also advised by the angel not to look back at his familiar home, which demonstrates a nostalgia for sin which must be overcome. This is also seen, said Pope Francis, in the Hebrews' nostalgia for "the onions of Egypt" while they were in the desert.

"Longing made them forget that they ate those onions on the table of slavery."

"Faced with sin, we must escape without any nostalgia." This tendency to nostalgia for sin is twinned with a "temptation to curiosity," he added.

"Curiosity does not help, it hurts," exclaimed the Pontiff. The desire to know "what is this sin like" is a harmful curiosity, and we must "run away and … not look back," he urged.

"We are weak, all of us, and we must defend ourselves."

There can be also a temptation to fear, "to be afraid to move forward on the faith of the Lord."

He stressed that there is a temptation that says it is "better to stay here," in a place of familiarity and comfort. "But this is the slavery of Egypt."

"I fear moving forward, I'm afraid of where the Lord will bring me," the Pope said. "Fear, however, is not a good counselor."

Faced with sin, nostalgia, and fear, our response must be a "looking to the Lord, contemplating the Lord."

"This gives us the beautiful wonder of a new encounter with the Lord."

In our temptations, we must have the courage to be humble and say to Christ, "Lord, I am being tempted: I want to stay in this situation of sin; Lord, I am curious to know about these things; Lord, I am afraid."

This, the Holy Father taught, will lead to the "stupor of a new encounter with Jesus."

"We must not be naive nor lukewarm Christians, but brave, courageous."

"We are weak, but we must be courageous in our weakness."