Warren Buffett has no shortage of wisdom when it comes to the importance of hiring people with integrity. Or the principle that we should invest in relationships with honest and ethical people.

Sounds pretty straightforward. Who wants to work with or do business with crooks? To illustrate his point, Buffett once asked a group of college students to imagine a classmate they felt they could invest in long-term in order to receive 10 percent of that person's earnings for the rest of their lives.

Here's what he said:

You would probably pick the one you responded the best to, the one who has the leadership qualities, the one who is able to get other people to carry out their interests. That would be the person who is generous, honest, and who gave credit to other people for their own ideas.

Honesty, generosity, giving others credit, and pouring into other people are the hallmarks of a powerful leadership philosophy I preach from stages across the country: servant leadership.

Several of the world's thought leaders and experts agree with Buffett's premise of investing in servant leaders. Because plain and simple, it just makes really good business sense. They also acknowledge the unquestionable traits that servant leaders embody, including: 

1. Selflessness

Raj Sisodia, co-founder of Conscious Capitalism, notes that "a leader who operates with a primary emphasis on self-interest naturally views other people as a means to that end. You cannot be a true leader if you operate at that level of consciousness."

2. Trustworthiness

Stephen M.R. Covey, the best-selling author of The Speed of Trust, points out that the positional leader seeks to control but a servant leader "seeks to unleash talent and creativity by extending trust to others." While counterintuitive for most, the servant leader fundamentally believes deeply in others -- and in their potential.

3. Vulnerability

Simon Sinek, author of three best-selling books, including Start With Why, notes that servant leaders intentionally create space in which a worker can walk into their boss's office to admit a mistake without fear of losing their job. "It means someone can raise their hand and ask for help, admit they have been given a responsibility they don't feel prepared or knowledgeable enough to complete, or admit they are scared without any fear of humiliation or retribution," shares Sinek.

4. Courage

Brené Brown, researcher and author of three No. 1 New York Times bestsellers, including Daring Greatly, believes a culture founded on servant leadership will crush a culture of shame and kill the fear that it breeds. One of the tenets of servant leadership, says Brown, is courage, which thereby increases engagement, innovation, creativity, productivity, and trust.

While the media and top tiers of traditional top-down organizations may be more apt to acknowledge the glorified contributors who help make their companies profitable, the leader Buffett advises us to invest in will praise and recognize all human contributors who make a difference, from the mailroom to the boardroom.