When someone is qualified, they are recognized as someone trained to perform a specific job or task. A level of competency is associated with this recognition.
The Bible speaks about qualities all Christians should strive to achieve. We may not achieve all of them, but we can still lead others.
Leadership is about influence. We strive to influence others for the cause of Christ. As a Christian, our qualification to lead others is built on the blood of Jesus.
The stronger our faith becomes, the more our confidence grows, and the greater our influence. This type of leadership is needed in the kingdom.