The following is an excerpt from The MacArthur New Testament Commentary on Ephesians 4 .

Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. And be kind to one another, tender–hearted, forgiving each other, just as God in Christ also has forgiven you. (Ephesians 4:31–32)

Man’s natural tendency is to sin, and the natural tendency of sin is to grow into greater sin. And a Christian’s sin will grow just like that of an unbeliever. If not checked, our inner sins of bitterness and wrath and anger will inevitably lead to the outward sins of clamor, slander, and other such manifestations of malice.

Bitterness (pikria) reflects a smoldering resentment, a brooding grudge–filled attitude (see Acts 8:23; Heb. 12:15). It is the spirit of irritability that keeps a person in perpetual animosity, making him sour and venomous, Wrath (thurmos) has to do with wild rage, the passion of the moment. Anger (orge) is a more internal smoldering, a subtle and deep feeling. Clamor (krauge) is the shout or outcry of strife and reflects the public outburst that reveals loss of control. Slander (blasphemia, from which we get blasphemy) is the ongoing defamation of someone that rises from a bitter heart. Paul then adds malice (kakia), the general term for evil that is the root of all vices. All of these, he says, must be put away from you.

These particular sins involve conflict between person and person—believer and unbeliever and, worse still, between believer and believer. These are the sins that break fellowship and destroy relationships, that weaken the church and mar its testimony before the world. When an unbeliever sees Christians acting just like the rest of society, the church is blemished in his eyes and he is confirmed still further in resisting the claims of the gospel.

In place of those vices we are rather to be kind to one another, tender–hearted, forgiving each other, just as God in Christ also has forgiven us. These are graces God has shown to us and they are the gracious virtues we are to show to others. God did not love us, choose us, and redeem us because we were deserving, but purely because He is gracious. “God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. … While we were enemies, we were reconciled to God through the death of His Son” (Rom. 5:8, 10). If God is so gracious to us, how much more, then, should we be kind, … tender–hearted, and forgiving to fellow sinners, especially to one another.

Being unconditionally kind characterizes the Lord, as Luke 6:35b shows: “For He Himself is kind to ungrateful and evil men.” Paul speaks of “the riches of His kindness … that leads you to repentance” (Rom. 2:4). We are to be like our heavenly Father, says Christ, and are to “love [our] enemies, and do good, and lend, expecting nothing in return; and [our] reward will be great, and [we] will be sons of the Most High” (Luke 6:35a).

Tender–hearted has the idea of being compassionate, and reflects a feeling deep in the bowels, or stomach, a gnawing psychosomatic pain due to empathy for someone’s need. Forgiving each other is so basic to reflecting Christlike character that it needs little comment. The most graphic illustration of forgiveness is in the parable of Matthew 18:21–35. When Peter asked about the limits of forgiveness, the Lord told him a story of a man with an unpayable debt who was forgiven by his creditor, the king. This was a picture of salvation—God forgiving a sinner the unpayable debt of unrighteous rebellion against Him.

The forgiven man then went to someone who owed him a small amount and had him imprisoned for nonpayment. He who eagerly accepted a massive, comprehensive forgiveness would not forgive a small, easily–payable debt of another person. The incongruity of his action shows the heinousness of a believer’s unforgiving heart, and the man was severely chastened by the Lord for his wicked attitude.

Paul has this same relationship in mind as he calls for believers to forgive just as God in Christ also has forgiven you. Can we who have been forgiven so much not forgive the relatively small things done against us? We, of all people, should always be eager to forgive.