Knowing the truth is not the same as knowing about the truth. You can know about Jesus but not know him at all. Once I had a guide on a Holy Land tour who knew more about Jesus than any of us in the group, but he was a Muslim. To preach the good news, we must preach Christ and not about Christ. Even in a Bible study class, the focus should be on the Lord. Focusing on all the peripheral details won't draw you closer to him. A Christian must live fully in the Lord and not just observe him from the side.