In his daily Mass, Pope Francis cautioned Christians not to be overly-critical of those who preach the Gospel, emphasizing that focusing too much on personal precepts keeps us from being happy.

Reflecting on the day's Gospel reading in which Jesus compares the generation to children who are always unhappy or dissatisfied, the Pope stated that "The people of God have a certain allergy to the preachers of the Word: they persecuted the prophets, (even) killed them."

The pontiff's Dec. 13 homily was directed at those who were present for his morning Mass in the Vatican's Saint Martha guesthouse.

Following the day's readings, Pope Francis explored the meaning of the Gospel passage, taken from Matthew, explaining that the unhappiness of the people in that generation was because they were "not open to the Word of God."

Their refusal to listen, he noted, had nothing to do with the message, but the messenger, adding that "They reject John the Baptist," who came "neither eating nor drinking," saying that he was "a man possessed."

They rejected Jesus, the Pope observed, referring to him as "a glutton, a drunkard, a friend of publicans and sinners," going on to say that the people always had a reason to criticize the preacher.

"The people of that time preferred to take refuge in a more elaborate religion," the Pope emphasized, "in the moral precepts, such as the group of Pharisees; in political compromise, as the Sadducees; in social revolution, as the zealots; in gnostic spirituality, such as Essenes."

"They were (happy) with their clean, well-polished system. The preacher, however, was not (so pleased)," the pontiff explained, recalling that Jesus reminded them of how their ancestors had treated the prophets in the same way.

These people, noted the Pope, claim to accept the truth, "but the preacher, preaching, no."

"They prefer a life caged in their precepts, in their compromises, in their revolutionary plans or in their (disembodied) spirituality."

"These Christians are closed, they are trapped, sad," observed the Pope, "these Christians are not free. Why? Because they are afraid of the freedom of the Holy Spirit, which comes through preaching."

Stating that "This, then, is the scandal of preaching," the pontiff recalled the words of Saint Paul in which the apostle referred to "the scandal of preaching that ends in the scandal of the Cross," adding that "that God should speak to us through men with limits, sinful men, scandalizes."

"And what scandalizes even more," stated the Pope, "is that that God should speak to us and save us by way of a man who says he is the Son of God but ends (his life) as a criminal. That scandalizes."

"These sad Christians," the pontiff observed, "do not believe in the Holy Spirit, do not believe in the freedom that comes from preaching, which admonishes you, teaches you – slaps you, as well – but it is the very freedom that makes the Church grow."

In seeing "these children who are afraid to dance, to cry, (who are) afraid of everything, who ask for certainty in all things," Pope Francis reflected, "I think of these sad Christians, who always criticize the preachers of the Truth, because they are afraid to open the door to the Holy Spirit."

Concluding his homily, the Pope urged the Mass attendees to "pray for them," and to "pray also for ourselves, that we do not become sad Christians, cutting off the freedom of the Holy Spirit to come to us through the scandal of preaching."