The following is a post I have posted elsewhere, in addition to my unique work here, I will post these theology posts from the River City blog as they appear.
In the first question we're posting at the River City Church blog, we're dealing with a specific verse and the subject of forgiveness, so let's start with the verse itself and get right into it.
“Pay attention to yourselves! If your brother sins, rebuke him, and if he repents, forgive him, and if he sins against you seven times in the day, and turns to you seven times, saying, ‘I repent,’ you must forgive him.” Luke 17: 3-4 ESV
The short answer here is yes…and no, however the short answer is incomplete.
As Christians, this verse calls us to forgive in a way that exceeds the cultural standards. The reason Jesus says: “Forgive seven times” is because in first century Hebrew (Jewish) culture, forgiving three times was honourable. So, Jesus here is telling us to go beyond what is culturally acceptable and forgive completely. So in that regard, forgiveness is not withheld until repentance. This is not the end of the matter, however.
In Christian doctrine, we have two phrases called “Limited Atonement” and “Unlimited Atonement” I won’t bore you with a long drawn out explanation of each, but the Wikipedia articles on each are pretty good. In a sentence they are this:
Limited Atonement: Jesus Christ's substitutionary atonement on the cross (His death) is limited in scope to those who are predestined to salvation and its primary benefits are not given to all of humanity but rather just believers.
Unlimited Atonement: Jesus died as a propitiation for the benefit of mankind without exception.
Each of these positions have strengths and weaknesses, and good solid evidence can be found for both in Scripture.
This has led to a rise in a third position which is relatively new and called “Unlimited Limited Atonement” which Pastor Mark Driscoll describes this way: “By dying for everyone, Jesus purchased everyone as his possession, and he then applies his forgiveness to the elect, those in Christ, by grace, and he applies his wrath to the non-elect, those who reject Christ. Objectively, Jesus’ death was sufficient to save anyone and, subjectively, efficient only to save those who repent of their sin and trust in him. This position is called unlimited limited atonement, or modified Calvinism (Death by Love: Letters from the Cross, pg. 171-172)”
All of that is background so that you understand me when I say this: As Christians, we are called to forgive people just as God has forgiven all of us through His son Jesus Christ, BUT for that forgiveness to be effective on the person who has sinned themselves, repentance is necessary.
Keep in mind as well that the verse says: “If your brother sins”. The term “brother” in this context is different than “neighbour”. Where neighbour would include all people, the term brother specifically refers to the believing community.
In short, forgiveness is not conditional on repentance from the point of view of the forgiver, but in order for that forgiveness to be effective on or received by the sinner, yes, repentance is necessary.
Yours in Theology
 It’s also because seven is the biblical number for “total” or “complete” so Jesus was telling us to “Completely forgive”.
 Further reading on these terms will lead to discussions on Lapsarianism, Supralapsarianism and Infralapsarianism, these discussions are FASCINATING…really…
 Which, in context, also includes and could be translated: brother or sister.