We tend to think that a good Bible study “leader” is simply someone who is knowledgeable, but after all these years, I realize the many great bible studies that I have had are the ones that every member contributes in sharing their portion of Christ. We exchange our ideas and exhort one another. The leaders, then, essentially serve the role of “facilitators”. They encourage fellowship among saints.
Also, good “leaders” are able to explain in words to people of various “maturity” levels in humility. This observation reminds me of the words of John Piper that,
“A good teacher can put himself in the place of a variety of learners and therefore explain hard things in terms that are clear from their standpoint.” – John Piper