Why is church discipline necessary according to the Bible?

The necessity of church discipline is rooted in maintaining both the purity of the church and the spiritual health of its members. In 2 Thessalonians 3:6, Paul commands believers to withdraw from those who walk disorderly, emphasizing the need for discipline when there are known, public sins that disrupt the church’s harmony and witness. This process is not punitive but restorative, aimed at helping the erring brother to recognize his sin, repent, and ultimately return to fellowship. The goal is to protect the church from division and distraction from the gospel while providing an avenue for the individual to be reconciled to God and the community. As stated in 1 Corinthians 5:6-7, a little leaven can leaven the whole lump; thus, maintaining discipline helps preserve the integrity of the body of Christ.