The usual answer is: “Yes, forgive everyone, whether they repent or not.”

Before we answer though we have to ask:

What is forgiveness?

“Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, ‘I repent,’ you shall forgive him.” (Luke 17:3-4)

Matthew Henry comments on this passage:

“You are commanded, upon his repentance, to forgive him, and to be perfectly reconciled to him: If he repent, forgive him; forget the injury, never think of it again, much less upbraid him with it.”

Think about that: “perfectly reconciled, forget the injury, never think of it again.”
That is Biblical forgiveness.

That is how God forgives us when He “casts all our sins into the depths of the sea” (Mic 7:19), to “remember them no more” (Heb 8:12), because “as far as the east is from the west, so far has He removed our transgressions from us” (Psa 103:12).
When God forgives He just-if-ies me; He treats me just-as-if-I had never sinned.
That is Biblical forgiveness.

But is this possible if there has been no repentance on the offender’s part?

• A husband is given to domestic violence and continually beats up his wife; he never repents. But each time the battered wife tells him: “It’s O.K. honey, I forgive you. We are perfectly reconciled, I forget the injury, I will never think of it again.”
• A young girl is repeatedly abused and raped by an adult, a near relative; he never repents. But each time she tells her abuser: “It’s O.K, I forgive you. We are perfectly reconciled, I forget the injury, I will never think of it again.”

Something is wrong here.

Admittedly, even if the violent husband or sexual abuser did genuinely repent, never to offend again, sensible boundaries would need to be in place. In the case of the abused wife it may be too late to save the marriage.
In a fallen world, sometimes we are limited in the extent to which a broken relationship can be restored. But if there is genuine repentance there can always be a measure of real reconciliation.

But, without repentance? Can there be any reconciliation at all?
What does “forgiveness” mean if there is no reconciliation at all?

Consider the following comments by R. C. Sproul [1] on Luke 17:3-4…

The New Testament has much to say about forgiveness, but often we can be very confused in our thinking on this subject. This passage is a mini-lesson on forgiveness and has much to teach us.

The appropriate response if a brother sins against you is to forgive him. Peter tells us that there is a love which covers a multitude of sins (1 Peter 4:8). We are not to keep accounts of people’s minor indiscretions.

But if somebody seriously violates us, we are called to bring that to the person’s attention. People’s words or actions can injure us severely, and they may not be aware of it, but they should want to know the effect they have had on us. So we are told to rebuke our brother, if he trespasses against us.
Jesus, however, is quick to add that if the erring brother repents, then he is to be forgiven.

But what if he doesn’t repent? Are you then under obligation to forgive him?
Christians sometimes think that they are required to forgive all people, whether they repent or not. But I cannot find that teaching in the New Testament.

There are places where Jesus and others convey that kind of forgiveness before there is repentance; for example when Jesus pleads with his Father from the cross to forgive those who have crucified him [though see below. KS]; or when Stephen cried out to God in the midst of his execution, ‘Lay not this sin to their charge.’
We are permitted to grant forgiveness where repentance is not present, but forgiveness is not automatically required.

The Bible makes provision for disciplinary action to be taken within a church, or to take one’s case before the civil magistrate. Similarly if somebody steals your property and refuses to repent, within the context of the biblical ethic it is permissible to involve the law to seek restitution.

All this may sound shocking or surprising, for forgiveness is so central to the New Testament, but notice that Jesus said that it was when the person repented that he was to be forgiven. But if repentance is there, we don’t have an option – we must forgive.

But how do we know whether the repentance is genuine? It is easy to say we are sorry, and Jesus obviously has that in view because he said, ‘If he sins against you seven times in a day, and seven times comes back to you and says, “I repent,” forgive him.’
If a person says he is sorry, even if he is insincere, we are required to forgive him. If his apology is not genuine, that is for God to deal with, but our duty is to forgive. Where there is no repentance we don’t have to forgive; but where there is repentance we must forgive.

But if we are going to understand what this text is getting at, we have to ask what it means to forgive someone? [emphasis K.S.]
Forgiveness in biblical terms means to hold a sin against a person no more. We are called to forgive and forget, because that is how God deals with us. The Bible teaches that when God forgives us, he casts our sins into the sea of forgetfulness and remembers them no more.

It would be absurd to interpret this to mean that the omniscient God suddenly suffers from amnesia, and can no longer recall that we had transgressed his law. God does not forget in that sense, but in a legal sense he forgets. He never brings charges against us again.
Authentic forgiveness means that if I say to you, ‘I forgive you’, I can never hold that against you again, nor mention it again to you or to anyone else.

Now that is not so much an attitude of the heart as a pattern of behaviour. We are not to keep a record of past offences. That is one of the hardest things in the world to do.
What Jesus is saying is, if a person sins against you, seven times in one day, but each time turns and says, ‘I am sorry’, you must forgive him.

(End comments by R. C. Sproul)

Gospel forgiveness is bound up in repentance

Jesus began His own Gospel ministry with these very words: “Repent, for the kingdom of heaven is at hand” (Matt 4:17).
He summarized His whole mission in terms of: “I did not come to call the righteous, but sinners, to repentance” (Matt 9:13).

Even on the cross, He did not say: “I forgive you all”; but He asked God: “Father, forgive them, for they do not know what they do” (Luke 23:34).
Seven weeks later the Father answered that prayer: 3,000 cried out, “Men and brethren, what shall we do?”; and Peter responded: “Repent, and let every one of you be baptized in the name of Jesus Christ for the forgiveness of sins” (Acts 2:37-38).

In this, Peter was doing just what Christ had told him and his fellow disciples to do when Jesus commissioned them and sent them out into the world to preach the Gospel. Jesus said:

“It was necessary for the Christ to suffer and to rise from the dead the third day, and that repentance and forgiveness of sins should be preached in His name to all nations, beginning at Jerusalem. And you are witnesses of these things.” (Luke 24:46-48)

Likewise, the apostle Paul saw his own commission in these terms. Before King Agrippa he recalled how Jesus had commissioned him, viz:

“I now send you to the Gentiles to open their eyes, in order to turn them from darkness to light, and from the power of Satan to God, that they may receive forgiveness of sins.” (Acts 26:17-18)

Paul understood this in terms of a ministry “to the Gentiles, that they should repent, turn to God, and do works befitting repentance” (Acts 26:20).

Repentance is never perfect

No one ever repents perfectly (seeing his sin fully as bad as it is, as God does), or exhaustively (seeing every last one of his sins, as God does).

Thankfully, in the end neither repentance, nor faith, saves us. Faith is just the hand that takes hold of Christ, and God in Christ saves us.
But without at least some credible degree of repentance,  faith is dead (Jas 2:26).

In forgiving each other we are not to look for what we might think is perfect repentance.
In some cases it may be blindingly obvious that a person’s repentance is not genuine, eg. if the “repentant” person, in a temper, slams the door, and yells sarcastically, “Oh well, I am very sorry, O.K.?”
But unless it is starkly obvious that he is not repentant we should give a person the benefit of the doubt and (as Sproul said) leave it “for God to deal with, but our duty is to forgive.”
Jesus’ words: “If he sins against you seven times in a day, and seven times in a day returns to you, saying, ‘I repent,’ you shall forgive him” at least imply we are not to be looking for ways to withhold forgiveness, but to be ready to give the benefit of the doubt.

Sadly, I have personally witnessed occasions where a counsellor has mindlessly used a checklist from 2 Cor 7:11: if the counsellor was not completely satisfied that each item from the list was checked off, the person’s “repentance” was dismissed as insincere.
This probably says more about the immaturity of the counsellor than the sincerity of the penitent.

Overlooking “minor indiscretions”

Though all sin is serious, “some sins in themselves, and by reason of several aggravations, are more heinous in the sight of God than others.” (Shorter Catechism Q. 83)
Of course, we ourselves should be ready to repent, at least to say “sorry”, no matter how minor our offence.

Nonetheless, we are foolish to make a federal case out of every perceived offence, however minor. Let us not join the woke culture about us that is perpetually offended.
Where the other’s offence is (what R. C. Sproul referred to as) a “minor indiscretion” it is good to be quick to forgive and forget. (Jas 1:19-20)

“The discretion of a man makes him slow to anger, and his glory is to overlook a transgression.” (Prov 19:11)

“Above all things have fervent love for one another, for ‘love will cover a multitude of sins’.” (1 Pet 4:8)

We are to be ready to do this all the time – whether in marriage, with friends, in the church, maybe in the workplace. And such forgiveness is to be genuine, resulting in being: “perfectly reconciled, forgetting the injury, never thinking of it again.”

Do not become bitter 

What if the offence is so serious that it would be impossible for a relationship to be restored without a credible measure of spoken repentance?
There is still a good way and a bad way to respond.
How? Jesus said:

“Love your enemies, do good to those who hate you, bless those who curse you, and pray for those who spitefully use you… love your enemies, do good” (Luke 6:27-28, 35).

Here, “loving your enemies” is not about having a warm, fuzzy feeling; it certainly doesn’t mean you are to love all people equally – whether wife, children, friend or enemy.
Nor does Jesus say that you are to automatically forgive your enemies where the offence is serious. (Only make sure it is “they”, and not “you”, being obstinate.)

But “loving your enemies” does mean you will “pray for him” and look to “do him good” – which, in the case of a serious offender, may even mean that to “rebuke him” (Luke 17:3) is the “goodest” you can do, and the best way you can “bless him”.

All of which will mean, even where there is no repentance for a serious offence, we should have a forgiving spirit that looks eagerly for any movement towards repentance on the offender’s part with the hope of being able to then forgive him and see the relationship in an appropriate measure restored.

[1] Sproul, R. C. (1999). A Walk with God: An Exposition of Luke (pp. 320–321). Christian Focus Publications.