More knowledgeable Christians should never mock or disdain weaker believers, nor should they become stumblingstones toward these brethren.
People's motives in serving Christ vary from pure to sinful. However, other men’s motives should not rob us of the joy of Jesus Christ being preached.
Paul was one of the most religious people ever to live. In spite of his religious efforts, he was condemned to hell until he trusted Christ as Saviour.
