"Proclaiming the Gospel must take the road of poverty," the Pope said at Mass June 11 in the chapel of the Domus Sanctae Marthae.

Those who preach and share the Gospel need to give witness to poverty, where the only abundant riches in their lives are the free and joyful gifts received from the Lord, he said.

The Pope, who concelebrated Mass with Archbishop Gerhard Muller, prefect of the Congregation for the Doctrine of the Faith, highlighted a line from the day's reading from the Gospel of Matthew: "Without cost you have received; without cost you are to give."

When Jesus told his apostles, "Do not take gold or silver or copper for your belts; no sack for the journey, or a second tunic, or sandals, or walking stick," he was urging them to proclaim the Gospel "with simplicity," Pope Francis said.

Simplicity allows the power of the Word of God and God's grace to grab the spotlight, he said. It also shows "the confidence" the apostles had in God's word because without it, "they would probably have done something else."

"Evangelical preaching flows from gratuitousness, from the wonder of the salvation that comes and that which I have received freely and must give freely," he said.

This was the experience of the early church as "St. Peter didn't have a bank account, and when he had to pay taxes, the Lord sent him to the sea to fish and find inside the fish the money for paying," the Pope said.

Also, he said, when Philip met the treasurer of an Ethiopian queen on the road from Jerusalem, Philip didn't see the moment as an occasion for business, to "set up an organization with him to support the Gospel."

"No! He did not strike a deal with him: he preached, baptized and left," the Pope said.

However, since the beginning, the temptation has always been there to seek strength elsewhere, beyond the freeness of salvation, he said.

This creates "a little confusion" and proclamation -- which the Lord invites people to engage in -- can become proselytism.

Pope Francis cited a phrase from Pope Benedict XVI's homily in Brazil in 2007, when the now retired Pope said, "The church does not engage in proselytism. Instead, she grows by attraction."

This attraction, Pope Francis said, comes from the witness of people who freely proclaim the free gift of salvation.

They also must walk the path of poverty, he said, where "I have no riches, my only wealth is the gift I received, God," and his free gifts of grace and of salvation.

"This gratuitousness, this is our wealth," he said.

The church must carry out its charitable work -- where money is necessary -- but it can be done with "a heart of poverty, not with the heart of an investor or an entrepreneur," he said.

It's this kind of poverty that "saves us from becoming managers, businessmen," he added. "The church is not an NGO."

Poverty and praising the Lord -- where "we are not asking, we are only praising" -- are two signs that an apostle of Jesus is living out the gift of God's grace, he said.

"When we find apostles that want to make the church rich and make a church without the gratuitousness of praise, the church becomes old, it becomes an NGO; the church becomes lifeless," the Pope said.