Vatican City, Jun 13, 2013 / 09:12 am

"It feels good," Pope Francis said today as he celebrated Mass in his native language of Spanish for the first time in 48 days.

"It's the first time I celebrate Mass in Spanish since February 26!" he exclaimed during his homily for daily Mass in the chapel of Saint Martha's House.

The Eucharistic celebration was attended by employees of Argentina's embassies and consulates, alongside staff of the United Nations Food and Agricultural Organization in Rome.

Pope Francis emphasized to them the importance of not speaking badly about other people, underscoring that "we lose if we are not able to keep our tongues in check."

"There is no need to go to a psychologist to know that when we denigrate another person it is because we are unable to grow up and need to belittle others, to feel more important," he said. "This is an ugly mechanism."

"In the end we are all traveling on the same road, we are all traveling on that road that will take us to the very end," the Pope said.

And if people do not choose a "fraternal" path, he warned, "it will end badly, for the person who insults and the insulted."

"Jesus, with all the simplicity says, 'do not speak ill of one another, do not denigrate one another, do not belittle one another,'" he said, referencing the day's Gospel reading from Matthew 5.

"Natural aggression, that of Cain toward Abel, repeats itself throughout history," noted the Pope.

He believes that the reason people insult is because "we are weak and sinners" and because "it is much easier to resolve a situation with an insult, with slander, defamation instead of resolving it with good means."

In Matthew's fifth chapter, Jesus tells the disciples that it is more important to make amends with others than to offer God sacrifices.

"Anger towards a brother is an insult, it's something almost deadly, it kills him," he said.

"If our heart harbors bad feelings towards our brothers, something is not working and we must convert, we must change," Pope Francis insisted.

The Holy Father gave a challenging assessment of the Christian life, saying that anyone who lives it will have greater demands made of them than others.

"Sometimes we go hungry and think, 'what a pity I didn't taste the fruit of a tasty comment against another person," said the pontiff.

"But that hunger bears fruit in the long run and is good for us," he said.

"I would ask the Lord to give us all the grace to watch our tongues, to watch what we say about others," he told the Argentinians.

He noted, "it is a small penance but it bears a lot of fruit."