"Don't go left, don't go right, go deeper." This has been the longtime mantra of Jim Wallis and his organization Sojourners, a Christian social justice group that he presides over and helped found in the 1970s. Today Wallis is a leading voice on the intersection of faith and politics, one often known to counterbalance the religious right (though he himself doesn't identify as liberal).

Wallis is the latest interviewee in The Washington Post's ongoing "On Leadership" video series, which explores the personal experiences that have shaped prominent figures' character and views of leadership. Watch the video above, in which Wallis shares a story he usually never tells — that of growing up with an debilitating stutter before making a career as a public speaker.