How do we know that false teachers are a threat to the church?

The threat posed by false teachers to the church is significant as they often come disguised in sheep's clothing while inwardly being ravenous wolves (Matthew 7:15). The Apostle Paul warns of their deceptive actions, stating that they introduce damnable heresies in a sly manner, seeking to gain the trust of believers through external show and hypocritical zeal. Their cunning craftiness can lead the unsuspecting astray, demonstrating the necessity for the church to be vigilant and discerning concerning the teachings they embrace. Ephesians 4:14 calls believers to grow in doctrine to avoid being tossed about by every wind of doctrine.