I have a brother in Christ that challenges every doctrine of belief. His heart is right and he is very dedicated to God and deep into ministries. But sometimes his questions cause division. For example, questioning the trinity, debating free will vs. election, questioning the divinity of Christ , question if works are a part of salvation, etc. These things divide us Christians instead of unite us and confuse new believers. They even cause me to question some things that I fear I ought not question. I know his heart is right, and he's not trying to 'serve his own appetites' but instead search for the truth. But sometimes I wonder if he's there because God wants me to question things deeper or if he's a stumbling block.