The Holy Bible clearly portrays God as punishing believers out of anger, as it is clear in cases such as after the Israelites worshiped the Golden Calf.
It is important for church pastors to teach their church members this truth about God. God does punish believers out of anger.
Why is it important to teach this? Because it is the truth. It is important for church members to understand who God really is.
More importantly, it is important for church members to understand that God punishes out of anger, because knowing this will help Christians refrain from doing things that will make God angry. God gets angry and can act out of anger against Christians.
Fear of the LORD is beginning of wisdom, the Holy Bible tells us. There is a reason why God wants us to fear Him. It is important that Christians fear God, because this is what God wants from Christians.