Speaking to some 8,000 people at a Catholic leadership conference, Bishop Robert Barron said on Tuesday that trust in the risen Christ should give us the courage to preach the truth boldly.

"Through the Holy Spirit, the ascended, risen Christ commands his mystical Body the Church to do what he did, and to say what he said. That's it…that's the task of the Church to the present day."

Barron, the auxiliary bishop of Los Angeles, is also the founder of Word on Fire Catholic Ministries and host of the award-winning "Catholicism" documentary.  

He delivered one of the opening keynotes at this year's Student Leadership Summit in Chicago. Known as SLS, the summit is hosted by the Fellowship of Catholic University Students (FOCUS) every other year. It aims to train student leaders and other ministers with tools for evangelization and missionary work, largely on college campuses.

This year's SLS drew more than 8,000 participants, more than double the attendance of the last summit, hosted in 2016 in Dallas with approximately 3,400 participants.

In his talk, Bishop Barron focused on the Acts of the Apostles, a Biblical book that he said "sets the agenda for us" in the work of evangelization.

He noted that this book begins with an account of Jesus' ascension, comparing Christ's glorified position in heaven to that of a general who commands his army at a vantage point from above.

"It tells us very clearly who's in charge, and what I mean by that is, the ascended Christ who now commands his Church."

Moving on from the Ascension to the account of Pentecost, Barron said that the descent of the Holy Spirit compels us to spread the Word of God. The Holy Spirit comes to earth to guide the Church, he said, led by the ascended Christ from heaven.

"In myriad ways, according to your particular missions, bring something of heaven to earth, doing as Jesus did," the bishop exhorted attendants.

In bringing the message of heaven to earth, Catholics should be careful not to water down the Gospel or fall for bland and uninspiring half-truths, he said.

He recalled an encounter that he had with Biblical scholar Scott Hahn, who remarked that "there is no historical basis for the for the claim that St. Francis said, 'Preach always, and when necessary, use words.'"

While indeed "our whole life should be a kind of preaching," Barron said, the statement attributed to St. Francis can become a problem when it is "used as a justification for a kind of pastoral reductionism," for example, the idea that "what it all really comes down to is taking care of the poor."

While caring for the poor is important, Barron said, this work "in and of itself can never be evangelically sufficient."

"This is not the time for anti-intellectualism in our Church! We have lots of young people, you know them, they're your friends and colleagues, who are leaving the Church for intellectual reasons," Barron said.

He called for a kind of "bold speech" needed to proclaim the Gospel, pointing to the preaching in the early Church, which challenged the widely held belief at the time that "Caesar is Lord."

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"The bold speech of the Church is that not 'Caesar,' or any of his colleagues or predecessors or successors, but rather Jesus is Lord, Jesus is the king. And he is also Christos, anointed."

The Roman empire at the time, Barron said, was rather liberal with regards to new religions, yet still rejected the early Christians because they identified Jesus – and not Caesar – as the only Lord.

"If he is Lord, everything in your life belongs to him. Your personal life, yes. Your body, yes. Your friendships, yes. Your political life, yes. Your entertainment, yes. All of it."

When Christianity becomes reduced to a mere message that can be gained from the dominant culture, Bishop Barron said, it moves from the faith of early persecuted Christians to one which is rewarded lavishly by others.

"That's what happens to a weakened, attenuated Christianity," he said.

"In the Acts of the Apostles we hear that when those first disciples spoke, people were cut to the heart. Still true, still true to this day. Bland spiritual teachings, saying what everybody else says, that won't cut anyone to the heart, but trust me, declaring the lordship of Jesus, that'll cut them to the heart."

Bishop Barron highlighted Jesus' role in light of the Old Testament, saying that only as a fulfillment of laws and the prophets does Jesus make sense. He pointed to St. Stephen's speech to the Sanhedrin before his martyrdom, in which the saint summarized the entire Old Testament and then described Jesus' ministry.

When Jesus is cut off from his roots in Israel, he becomes just a philosopher or wise figure, a "flattened out, uninspiring Jesus," the bishop warned.

In contrast, he said, "when you present Jesus as the fulfillment of the great story of Israel, Jesus as the fulfillment of the temple that was meant to bring humanity and divinity together, when you preach him as the fulfillment of the law and the covenant and the Torah, when you preach him as the culmination of all the proclamation of the prophets, people will be cut to the heart."

Bishop Barron related a story he commonly tells of a little girl he met while working in Chicago who presented to him a detailed account of George Lucas' "Star Wars" movies. He said that kids' aptitude to memorize such complex plotlines and character names dispels the notion that they cannot understand the Bible.

"This great, rollicking, complex, rich story that we have, full of weird names, yeah, but no weirder than Obi-Wan Kenobi, right? The kids have no trouble with that. Don't tell me they can't understand the Bible. And therefore don't tell me that they can't appreciate Jesus as the culmination of that great story."

The bishop ended his talk by encouraging conference attendees in prayer and asking them to help "remind the world whom they are to worship."

"Everybody worships somebody or something," he said. "Everyone's got a king, right? Our job is to stand up boldly and say, 'No, Christ is your king. Everything in your life belongs to him'."