Justin Taylor writes:

The following notes are from Jonathan Leeman’s short and very helpful book, Church Discipline: How the Church Protects the Name of Jesus (Wheaton: Crossway, 2012).

3 Forms of Discipline

Formative discipline helps to form the disciple through instruction.

Corrective discipline helps to correct the disciple through correcting sin (Matt. 18:15-17; Gal. 6:1; Eph. 5:11; Titus 3:10; 2 Thess. 3:14-15; 1 Cor. 5:1-13).

Preemptive discipline disallows someone from participating in the fellowship of the church in the first place (2 John 2:9-10; see an example of this in Acts 8:17-24).

The following notes have to do with “corrective discipline.”

6 Reasons Churches Should Practice Church Discipline

Church discipline is biblical.
Church discipline is an implication of the gospel.
Church discipline promotes the health of the church.
Church discipline clarifies and burnishes the church’s witness before the nations.
Church discipline warns sinners of an even greater judgment to come.
Most importantly, church discipline protects the name and reputation of Jesus Christ on earth.

4 Ways Church Discipline Demonstrates Love

Church discipline shows love for the individual, that he or she might be warned and brought to repentance.
Church discipline shows love for the church, that weaker sheep might be protected.
Church discipline shows love for the watching world, that it might see Christ’s transforming power.
Church discipline shows love for Christ, that churches might uphold his holy name and obey him.

5 Purposes of Church Discipline from 1 Corinthians 5

1. Discipline aims to expose.

Sin, like cancer, loves to hide. Discipline exposes the cancer so that it might be cut out quickly (see 1 Cor. 5:2)

2. Discipline aims to warn.

A church does not enact God’s retribution through discipline. Rather, it stages a small play that pictures the great judgment to come (v. 5). Discipline is a compassionate warning.

3. Discipline aims to save.

Churches pursue discipline when they see a member taking the path toward death, and none of their pleading and arm-waving causes the person to turn around. It’s the device of last resort for bringing an individual to repentance (v. 5).

4. Discipline aims to protect.

Just as cancer spreads from one cell to another, so sin quickly spreads from one person to another (v. 6).

5. Discipline aims to present a good witness for Jesus.

Church discipline, strange to say, is actually good for non-Christians, because it helps to preserve the attractive distinctiveness of God’s people (see v. 1). Churches, remember, should be salt and light. “But if the salt loses its saltiness . . . ,” Jesus said, “It is no longer good for anything except to be thrown out and trampled by men” (Matt. 5:13, NIV).

4 Foundational Assumptions for Church Discipline

1. An expectation of transformation.

The new covenant promises that Christ’s people will live transformed lives through the power of the Spirit. Even if change comes slowly, churches should expect change—the visible fruit of God’s grace and Spirit. Discipline is the right response to a lack of visible fruit, or, even more, the presence of bad fruit.

2. The work of representation.

Christians are to be little Christs, representing Jesus on earth. The concept of representation depends on the idea that Jesus is Savior and Lord; it depends on the fact that Christians are given a new status and a new work. Discipline is the right response when Christians fail to represent Jesus and show no desire for doing so.

3. The local church’s authority.

Jesus gave the local church the authority of the keys to officially affirm and oversee citizens of his kingdom. Churches do not make people Christians. The Spirit does that. But churches have the declarative authority and responsibility for making public statements before the nations about who is and isn’t a Christian. A church’s act of excommunication, therefore, does not consist of physically and forcibly removing the individual from its public gatherings, as if the church had the state’s power of the sword to physically move people’s bodies; rather, it consists of the public statement that it can no longer vouch for an individual’s citizenship in heaven. Excommunication is a church’s declaration that it can no longer affirm that an individual is a Christian.

4. Membership as submission.

Christians are called, as a matter of obedience to Christ, to submit to the affirmation and oversight of local churches. When threatened by a possible act of disci­pline, therefore, church members cannot simply preempt the church’s action with a resignation. That would be analogous to an individual resigning his national citizenship before a court could prosecute the criminal activity for which he had been indicted.

5 Principles for the Process of Church Discipline

The process should involve as few people as possible for yielding repentance.
When the process moves beyond one or several people, church leaders should lead the process.
The length of the process depends on how long it takes to establish that a person is characteristically unrepentant.

Individuals should receive the benefit of the doubt until the evidence indicates otherwise.
Leaders should involve and instruct the congregation as appropriate.
What Excommunication Signifies

“The church removes its public affirmation by barring the member from the Lord’s Table. It takes away his passport and announces that it can no longer formally affirm the individual’s citizenship in Christ’s kingdom” (p. 50).

1 of 3 Conclusions Churches Need to Arrive at before Determining It Is Time to Act

When a church becomes convinced that a person is genuinely repentant, it should not proceed with any form of discipline (and I cannot think of a single exception to this principle).
When a church becomes convinced that a person is characteristically (not temporarily) unrepentant, it should proceed with excommunication.

When a sin is so deliberate, repugnant, and indicative of a deep double-mindedness that a congregation is left unable to give credence to a profession of repentance, at least until time has passed and trust has been re-earned, it should pro­ceed with excommunication, determining to test for repentance after the fact.

See also, Pastors, Don’t Let Your People Resign into Thin Air and 22 Mistakes Pastors Make about Church Discipline.