In Luke 17:3 we are told to forgive if repentance takes place and in Ephesians 4:32 "Be kind to one another, tender-hearted, forgiving each other, just as God in Christ also has forgiven you," but in Mark 11:25 Christ says "Whenever you stand praying, forgive, if you have anything against anyone, so that your Father who is in heaven will also forgive you your transgressions." It seems as though the idea of extending forgiveness without repentance from the offender is encouraged in Mark 11 but discouraged in Luke 17 and Ephesians 4. Could you help give some clarity on this?
You can read each passage in isolation and might conclude there is a conflict because different passages on the same topic offer different viewpoints on the subject, or you can read all the various viewpoints and realize that a single truth is being expressed. "The entirety of Your word is truth, And every one of Your righteous judgments endures forever" (Psalms 119:160).
Just because one passage doesn't mention all aspects, it doesn't mean those aspects can be ignored. There isn't one passage that tells us everything about salvation, but we understand that we must do everything connected to salvation to be saved. It is true that Mark didn't mention repentance in "And whenever you stand praying, if you have anything against anyone, forgive him, that your Father in heaven may also forgive you your trespasses" (Mark 11:25). But what does it mean to forgive?
God teaches that we must forgive in order to be forgiven. "For if you forgive men their trespasses, your heavenly Father will also forgive you. But if you do not forgive men their trespasses, neither will your Father forgive your trespasses" (Matthew 6:14-15). Yet, Jesus mentioned that a person needs to repent. "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 17:4). This, we know is the way that God treats us. He is willing to forgive our sins if we repent. "The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance" (II Peter 3:9).
What you've overlooked is this means that in my desire to forgive someone who wronged me, I need to encourage him to change. "Therefore if you bring your gift to the altar, and there remember that your brother has something against you, leave your gift there before the altar, and go your way. First be reconciled to your brother, and then come and offer your gift" (Matthew 5:23-24). When you have a problem with a brother, you don't continue your life pretending it isn't there. You actively work to get it resolved. "Moreover if your brother sins against you, go and tell him his fault between you and him alone. If he hears you, you have gained your brother" (Matthew 18:15). In fact, to say nothing to someone who is in the wrong will jeopardize my salvation.
"When I say to the wicked, 'You shall surely die,' and you give him no warning, nor speak to warn the wicked from his wicked way, to save his life, that same wicked man shall die in his iniquity; but his blood I will require at your hand. Yet, if you warn the wicked, and he does not turn from his wickedness, nor from his wicked way, he shall die in his iniquity; but you have delivered your soul. Again, when a righteous man turns from his righteousness and commits iniquity, and I lay a stumbling block before him, he shall die; because you did not give him warning, he shall die in his sin, and his righteousness which he has done shall not be remembered; but his blood I will require at your hand. Nevertheless if you warn the righteous man that the righteous should not sin, and he does not sin, he shall surely live because he took warning; also you will have delivered your soul" (Ezekiel 3:18-21).
Taken as a whole, forgiveness is not a passive thought that is done in isolation. It is shown in what a person does to resolve the conflict. Imagine the idea of leaving a person in sin, never saying anything to him, but then saying you forgave him so you aren't responsible anymore. There is no real forgiveness there. You don't leave a person you care about in danger. When that conflict is resolved, then you can go to God after forgiving your brother's wrongs. The willingness to forgive and the desire to forgive must always be there. Whether it can be joyfully extended depends on the other person's willingness to do what is right.