Before Martin Luther King Jr. galvanized a nation with one of the greatest speeches of the 20th century, he had honed his delivery and storytelling skills through years of experience behind the pulpit as a Baptist minister.  He became a pastor at the age of 25 and delivered his famous “Dream Speech” nearly a decade later, giving him plenty of opportunities to sharpen his craft.

Many of the most gifted public speakers in our society are faith leaders. One gratifying benefit of writing books and columns on communication skills is the opportunity to reach an audience that extends beyond the “target market” of sales and business leaders. I constantly hear from spiritual leaders across religious denominations—priests, pastors, ministers, and rabbis—who work on their speaking skills deliver more inspiring sermons. Their messages are different, their traditions are different, but their goals are the same—to inspire their audiences and to give them a reason to return to church or synagogue the next week.

By understanding the needs and the challenges of our spiritual leaders I’ve also learned to appreciate just how much business leaders can learn from those whose job it is to inspire their congregations. In fact, many of the words we use to define great communicators in business are based in the spiritual tradition. We look to business leaders to “inspire” us. In many companies the best presenters carry the title, “evangelist.” We call especially persuasive CEOs “charismatic,” capable of “converting” prospects into customers. They are “passionate” leaders who have “a calling” and inspire us to a “higher purpose.”

With that said, here are three valuable communication lessons I’ve learned from some of the faith leaders I’ve met; lessons that apply to anyone who wants to deliver more persuasive, inspiring, and electrifying presentations.

Inspiring speakers keep their presentations to 18 minutes or less. The famous TED talks are limited to 18 minutes in length because TED organizers discovered that 18 minutes was an ideal amount of time to have a substantive discussion on a topic without putting an audience to sleep. Some research shows that an audience will begin to lose its attention after just 10 minutes. Some ministers I’ve met are adamant about following the 10-minute rule and will not give a sermon that lasts a minute more. I think an effective presentation can be delivered in the 10 to 18 minute range. Remember, Dr. Martin Luther King, who knew a few things about inspiring an audience, kept his Dream Speech to just under 18 minutes. If you can’t get point across in 18 minutes or less, keep working on the message until you can.

Inspiring speakers practice their presentations, a lot. Recently I had the opportunity to interview famed Christian pastor Joel Osteen, who I wrote about in this article. Osteen speaks to 50,000 people a week in person and reaches millions of others on television. He doesn’t “wing it.” Osteen told me that he rehearses his sermon six hours a week before he delivers it to a live audience. When I interviewed some of the most popular TED speakers of all time I learned that some of them practiced their presentation up to 200 times. Speakers who make it look ‘effortless’ put in a lot of effort to make it look that way.

Inspiring speakers ‘shine brightly’ on and off-stage. A common theme in many spiritual traditions is the idea of walking the talk. People don’t judge leaders on their words as much as they evaluate leaders on their actions. As an inspirational leader, it’s not enough for you to talk a good game. Your behavior must reflect your message.

For example, I know a CEO who runs a large technology company that touches your life every day. He preaches the gospel of teamwork in many of his internal presentations. If he didn’t act like someone who embraces and celebrates every member of his team, his message would fall flat. One day I met a security guard who works at this particular company.

“He’s very inspiring. A great guy,” the guard said about the CEO.

“How do you know?” I asked.

“Hundreds of people come into the lobby every day and walk right past me. He’s the only one who stops, shakes my hand, and thanks for me keeping the building secure.”

This particular CEO walks the talk.

Shining brightly also means having a positive outlook, a spring in your step, and a smile on your face. “An evangelizer must never look like someone who has just come back from a funeral,” Pope Francis once wrote. He said that ministers and clergy must be “animated by the fire of the spirit so as to inflame the hearts of the faithful.”

Isn’t role your role as a leader to inflame the hearts of the faithful? Your words can only take you so far. Words can and do inspire, but nothing is more persuasive than seeing a leader’s actions back their public words.

Fr. Mark Wiesner, pastor of St. Charles Borromeo in Livermore, California, received his college degree in Rhetoric and Communications. On the subject of inspirational leadership he once told me, “Communication is enhanced when those you are speaking to know you genuinely care about them. Whether they’re employees, clients, or parishioners, if those listening to you believe you have a vested interest in their well being, they’ll listen; even if what you have to say is difficult or challenging.”

Business leaders are faced with some of the same challenges as spiritual leaders who run places of worship. Nobody has to be there. They can leave for another place, another company. They choose to stay for the culture. They stay because they’re inspired. They stay because they feel as though their work gives their life meaning and purpose. Inspiring business leaders give their people a reason to stay, a reason to believe, and a reason to evangelize the cause.