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.
Separation is scriptural under a variety of different scenarios. Most commonly, believers understand that they are to separate from unbelievers (2 Corinthians 6:14). This does not imply that believers should not witness to the lost but that there should be no “fellowship” between the two. The Bible also indicates that there are times in which one believer should separate from another believer. Most often, this happens because of the propagation of false doctrine (Romans 16:17-18; 2 Thessalonians 3:6) or immoral practices (1 Corinthians 5:11). However, there may also be instances when believers separate for the purpose of furthering the work of God (Galatians 2:6-9).