The following is an excerpt from The MacArthur New Testament Commentary on Matthew 18.

And if your brother sins, go and reprove him in private; if he listens to you, you have won your brother. But if he does not listen to you, take one or two more with you, so that by the mouth of two or three witnesses every fact may be confirmed. And if he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, let him be to you as a Gentile and a tax-gatherer. Truly I say to you, whatever you shall bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven. Again I say to you, that if two of you agree on earth about anything that they may ask, it shall be done for them by My Father who is in heaven. For where two or three have gathered together in My name, there I am in their midst. (18:15–20)

God’s desire for His children here on earth is purity of life. It is impossible to study Scripture attentively and not be overwhelmingly convinced that God seeks above all else for His people to be holy and that He is grieved by sin of any kind. Directly quoting God’s command to His Old Covenant people Israel, Peter wrote the same command to Christ’s church: “You shall be holy, for I am holy” (1 Pet. 1:16; cf Lev. 11:44).

Because God is so concerned for the holiness of His people, they should be equally concerned. The church cannot preach and teach a message it does not live and have any integrity before God, or even before the world. Yet in many churches where there is no tolerance for sin in principle there is much tolerance for it in practice. And when preaching becomes separated from living, it becomes separated both from integrity and from spiritual and moral effectiveness. It promotes hypocrisy instead of holiness. Divorcing biblical teaching from daily living is compromise of the worst sort. It corrupts the church, grieves the Lord, and dishonors His Word and His name.

It is not surprising, therefore, that public discipline for sin is rare in the church today. Where there is little genuine desire for purity there will also be little desire to deal with impurity. The misinterpreted and misapplied statement of Jesus that we should not judge lest we be judged (Matt. 7:1) has been used to justify the tolerance of every sort of sin and false teaching. The ideas that every person’s privacy is essentially to be protected and that each is responsible only to himself have engulfed much of the church. Under the guise of false love and spurious humility that refuse to hold others to account, many Christians are as dedicated as some unbelievers to the unbiblical notion of “live and let live?” The church, however, is not nearly so careful not to gossip about someone’s sinning as it is not to confront it and call for it to stop.

The church has always had need for confronting the sins of its people. During its early days many foreign visitors to Palestine were converted to Christ and decided to stay in or near Jerusalem in order to enjoy the fellowship of believers there. A large number of native Jewish converts were ostracized from their families and lost their jobs because of their new-found faith. To help support those needy brothers and sisters, many of whom were virtually destitute, the believers who had property and possession sold them and gave the proceeds to the apostles, who “distributed to each, as any had need” (Acts 4:35). That practice was the spontaneous reaction of generous, Spirit-filled hearts to meet the practical needs of fellow Christians.

During that time, a couple named Ananias and Sapphira sold a piece of their property and pledged to God that they would give all the proceeds to the apostles for use in the church. Somewhere in the process, however, they decided to keep back a portion of the pledged money for themselves. In order not to appear less generous than their fellow believers, however, they falsely reported that they were giving the full amount. When the Lord revealed the duplicity to Peter, he first confronted the husband. “Ananias,” he asked, “ ‘why has Satan filled your heart to lie to the Holy Spirit, and to keep back some of the price of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not under your control? Why is it that you have conceived this deed in your heart? You have not lied to men, but to God.’ And as he heard these words, Ananias fell down and breathed his last.” Several hours later, Sapphira came to the apostles, not knowing what had happened to her husband. When Peter asked her if the property was sold for the price claimed by her husband, she confirmed his lie and suffered his fate. Not surprisingly, “great fear came upon the whole church, and upon all who heard of these things” (Acts 5:1–11).

The selfishness of Ananias and Sapphira was deplorable, but their great sin was in lying about what they had done, not only to the church but to God. In this particular case in the early church, God took discipline directly into His own hands and demonstrated before all how sin is to be dealt with by removing the offenders from the church and from the earth! The purity of the church not only was protected by making God’s people more fearful of sin but also by helping to keep out of the fellowship those who were not true believers (v 13).

Even in apostolic times, such direct and severe divine intervention in chastening apparently was rare, although Paul reports that some of the Corinthian believers became weak, ill, and even died as the result of gross immorality and disregard for the sacredness of the Lord’s Table (1 Cor. 11:30; cf 1 John 5:16–17). God has not changed His attitude about sin or about purity. He is every bit as much concerned for the holiness of His people today as He was when the church was born. Sin has to be dealt with or it will destroy both those who practice it and those who tolerate it. God may still act in supernatural ways to purge the church, but He has primarily given that responsibility to the church itself. The church must be “self-policing” with regard to sin. The horrendous scandals that have tarnished the church recently reflect the abysmal failure of believers to confront sinning leaders and followers. The world often has had to expose what the church tried to cover up.

The Lord has always disciplined His people, and He has always instructed His people to discipline themselves. Old Testament believers were told not to “reject the discipline of the Lord, or loathe His reproof, for whom the Lord loves He reproves, even as a father, the son in whom he delights” (Prov. 3:11–12). Just as human fathers discipline their children out of love in order to make them better, so God does with His children. Human parents know that instruction to their children without enforcement is futile. Children not only must be told what is fight but must be led to do what is right, by correction, rebuke, and often punishment. “He who spares his rod hates his son, but he who loves him disciplines him diligently” (Prov. 13:24). Contrary to much popular thinking, even among Christians, it is not love but indifference that causes parents to allow their children’s misbehavior to go uncorrected. “Discipline your son while there is hope,” the writer of Proverbs wisely advises (19:18; cf 22:15; 23:13).

After quoting the proverb (3:11–12) mentioned above, the writer of Hebrews says,

It is for discipline that you endure; God deals with you as with sons; for what son is there whom his father does not discipline? But if you are without discipline, of which all have become partakers, then you are illegitimate children and not sons. Furthermore, we had earthly fathers to discipline us, and we respected them; shall we not much rather be subject to the Father of Spirits, and live? For they disciplined us for a short time as seemed best to them, but He disciplines us for our good, that we may share His holiness. All discipline for the moment seems not to be joyful, but sorrowful; yet to those who have been trained by it, afterwards it yields the peaceful fruit of righteousness. (Heb. 12:7–11)

It is an illusion to think that the church can take a strong verbal stand against sin without enforcing that stand among its own members and at the same time expect them to conform to God’s standards of holiness. Physical children do not respond to that approach in discipline, and neither do spiritual children. Because of the remaining sinfulness of the flesh, Christians still have a strong bent toward disobedience. Without enforcement of its standards, holiness will never flourish. That is why discipline is so essential to the spiritual well-being of a church.

The foolish, pretentious, and sometimes immoral actions of a few highly visible figures in the evangelical church today have caused evangelicalism to become a byword among many liberal Christians and in the world at large. Such lack of integrity is often rightly depicted as the epitome of religious superficiality, self-indulgence, and hypocrisy.

It is with the church’s responsibility to keep itself pure that Jesus deals in Matthew 18:15–20. He is still teaching about the childlikeness of believers, illustrated by the young child He had called to Himself and set before the Twelve (v. 2). He had declared that a person enters and is considered great in the kingdom by becoming like a little child (vv. 3–4) and that, once in the kingdom, believers are to be protected like little children (vv. 5–9) and cared for like little children (vv. 10–14). He now declares that they must also be disciplined like little children.

In verses 15–20 Jesus presents five elements involved in godly discipline of sinning believers: the person who receives discipline, the person who initiates it, the purpose of it, the process and place for it, and the authority for it.