God designed the church community as a vital part of His plan. Through it, believers grow and mature in Christ Jesus. It is a haven of spiritual growth, biblical truth, encouragement, comfort, accountability, and correction. Yet, this same community can be endangered by the creeping influences of sin and stubbornness. The author of Hebrews instructed the readers to pursue peace and holiness and to protect the community from any poison that can lead to a falling away from the gospel and the community. Another term for that is apostasy.
Peace and harmony must be pursued, but sin must not be tolerated. If sin is not addressed in a church community, it will spread and produce devastating outcomes. The root of bitterness represents a hidden danger, and it can spread fast, especially if the church members are not vigilant.