A welcoming attitude to other people, especially the needy and including those who have different beliefs, is needed to effectively preach the Gospel, Pope Francis said in the last homily of his July 5-13 pastoral visit to South America.

"How many times do we see evangelisation as involving any number of strategies, tactics, manoeuvres, techniques, as if we could convert people on the basis of our own arguments?" said the Pope as he celebrated Mass at the Campo Grande in the Nu Guazú park of Paraguay's capital, Asuncion.

"The Lord says to us quite clearly: in the mentality of the Gospel, you do not convince people with arguments, strategies or tactics. You convince them by learning how to welcome them."

The Pope made his homily while standing in front of an altar that locals made out of rice and coconuts. The Pope first visited the countries of Ecuador and Bolivia, the Catholic News Agency wrote.

The Gospel where the pontiff's sermon is based comes from Matthew in which Jesus commissions his disciples two by two.

When Jesus sent out the disciples, he instructed them very clearly to "take nothing for the journey except a staff; no bread, no bag, no money," and "when you enter a house, stay there until you leave the place."

At the centre of Jesus' command is to "welcome," said the Pope.

"Jesus as the good master, the good teacher, sends them out to be welcomed, to experience hospitality," the Pope said, underlining that Jesus commissioned the disciples not as men with influence but to teach that "the Christian journey is about changing hearts."

"It is about learning to live differently, under a different law, with different rules. It is about turning from the path of selfishness, conflict, division and superiority, and taking instead the path of life, generosity and love."

The Pope said the "Church is the home of hospitality," likening it to a mother who welcomes those who are in greatest need with an open heart.

"How much good we can do, if only we try to speak the language of hospitality, of welcome! How much pain can be soothed, how much despair can be allayed in a place where we feel at home! Welcoming the hungry, the thirsty, the stranger, the naked, the sick, the prisoner, the leper and the paralytic."

The head of the Roman Catholic Church also emphasised the importance of welcoming those who think differently, those who do not have faith or lost it, the persecuted, the unemployed, and those who live in a different culture.

He stressed how crucial it is to welcome sinners, saying isolation is an evil that "eats away at our life."

"There is a bitter root which causes damage, great damage, and silently destroys so many lives. There is an evil which, bit by bit, finds a place in our hearts and eats away at our life: it is isolation."

Isolation "makes us turn our back on others, God, the community. It makes us closed in on ourselves," he said. That is why the true work of the Church is "to learn how to live in fraternity with others."

The day before, the Pope told the young people of Paraguay that happiness comes from making a more fraternal world.

"Youth is a time of high ideals," Pope Francis said at the Leon Condou stadium in Asuncion. "It is important that you, the young, realise that genuine happiness comes from working to make a more fraternal world!"

"It comes from realising that happiness and pleasure are not synonymous. Happiness is demanding, it requires commitment and effort. You are too important to be satisfied with living life under a kind of anaesthesia!"

Pleasure, the Pope said, is fleeting while "happiness is a dream that builds, that constructs."