I need forgiveness.  I feel like I am worse than Paul, at times, when it comes to being the worse sinner of us all.
"I do not understand what I do. For what I want to do I do not do, but what I hate I do.  As it is, it is no longer I myself who do it, but it is sin living in me.  I know that nothing good lives in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out." - Romans 7:15, 17,18 
"But for that very reason I was shown mercy so that in me, the worst of sinners, Christ Jesus might display his unlimited patience as an example for those who would believe on him and receive eternal life." - 1 Timothy 1:16 

What is the difference between forgiveness provided by Christ through His death on the cross and the forgiveness He says He will NOT give unless we forgive others?  How is it that a believer can be saved/born again, his/her sins forgiven, the penalty of sin paid for in full and yet God says He will hold sins against them if they do not forgive others?  How does this translate?  If we forget or choose not to forgive and Christ returns, does our unforgiveness merit a mark against our works for the kingdom?

Paramount to receiving forgiveness is to give forgiveness.  This teaching is found in many Scripture passages.
Matthew 6:15 says, "But if you do not forgive men their sins, your Father will not forgive your sins."
Mark 11:25 says, "And when you stand praying, if you hold anything against anyone, forgive him, so that your Father in heaven may forgive you your sins."
Luke 6:37 says, "Do not judge, and you will not be judged. Do not condemn, and you will not be condemned. Forgive, and you will be forgiven."
John 20:23 says,  "If you forgive anyone his sins, they are forgiven; if you do not forgive them, they are not forgiven."
2 Corinthians 2:10 says, "If you forgive anyone, I also forgive him. And what I have forgiven--if there was anything to forgive--I have forgiven in the sight of Christ for your sake,"
Ephesians 4:32 says, "Be kind and compassionate to one another, forgiving each other, just as in Christ God forgave you."
Colossians 3:13 says,  "Bear with each other and forgive whatever grievances you may have against one another. Forgive as the Lord forgave you."
This teaching goes right in line with another piece of Scripture, Matthew 7:12 - "So in everything, do to others what you would have them do to you, for this sums up the Law and the Prophets."  If we could all keep this in the forefront of our mind, forgiveness would come to us easier - as would a lot of other virtues.   If it is important enough to say blatantly in seven passages of the Bible then I think God thinks it important too.

The story of the Unmerciful Servant in Matthew 18:21-35 is a lesson on forgiveness.  The Lord's concluding remarks - "This is how my Heavenly Father will treat each of you unless you forgive your brother from your heart." - should set off bells and whistles, red flags and the like to take notice of why Father God would treat  believers like this or what would warrant such a reaction from God. 

"Each subject in a parable is symbolic.  The master represents the Lord, the servant is you and I, and the fellow servant is the one who sins against you.  The debt is our sin, the prison is whatever emotion locks up our reason, and the jailer who tortures us is Satan.

Please understand that failure to forgive each other doesn't suspend our salvation.  Salvation is not behavior driven like this parable is.  Salvation is belief driven.  What's being suspended until the debt is repaid is the relationship.  The servant doesn't stop being a servant.  [And us as Sons and Daughters doesn't stop being thus - my words.]  He no longer has access to the master, and the jailer now has access to him, but the implication is that once the debt is repaid he'll be restored to the master's good graces.

It helps when you see that there are 2 levels of forgiveness; one that comes through belief and one that is the result of behavior.  The first is the forgiveness that the Lord purchased with His life.  ...the other level, what I call fellowship.  Fellowship is temporal, carries earthly benefits, and is subject to interruption.  God can't relate to us while our hearts are full of anger, lust, envy, greed, or any other of the destructive human emotions that imprison us, because during those times we're like the unmerciful servant, needing discipline.  In the context of the parable, He's still our Master and we're still His servants, but we can't enjoy the full benefits of the relationship.  Something's come between us that has to be resolved before we can go on.  More often than not, it's our failure to forgive someone who's wronged us.

Depending on the intensity of our emotions and the determination with which we justify and cling to them, we may lose out on blessings and experience other deprivations like the limited loss of protection from our enemy.  Justified or not, these emotions are called sin in the Bible.  They make us impure and give the enemy access to us.  The Lord permits this access (Job 1:12).  Being unable to tolerate the presence of sin and unwilling to interfere with our choices, He can't do otherwise.  But as soon as we ask, we're forgiven and the sin is forgotten, the price having been paid at the cross and we're back in fellowship.  Then the Lord turns that which Satan had intended as torment into a blessing, showing that all is forgiven (Job 42:10-17). 

Complicated by human standards, it's exquisitely simple by God's. When wronged by a brother, you suffer. By staying angry and refusing to forgive, you wrong your brother and suffer again. But when you forgive him he is convicted and he suffers. In Rom 12:17-21, Paul says it's like heaping burning coals on his head. Meanwhile, the Lord takes the anger from your heart, restores you to fellowship with Him, and gives you peace. When you punish someone by failing to forgive them, do you realize you're the one who suffers most?
(Jack Kelley, Forgiveness article,  http://www.raptureready/)

The next parts of the equation to forgiveness are - repenting, and the difference from forgiving. In addition, is there a limit to our forgiveness of others?

"The word repent means to change your mind, not your behavior.  That's why the Lord said, 'If he sins against you seven times in a day, and seven times comes back to you and says, 'I repent', forgive him.'  It's also why in Matthew 18:22 He corrected Peter 'not 7 times, but 70 times 7.'  both passages cover repetitive commission of the same sins as well as sequential commission of different ones.

Just as repent doesn't mean, "I'll never do it again," forgive doesn't mean, "It's OK to do it again." Remember forgive means to lay aside or leave alone. Neither word is behavior driven. Both are perception driven. Jesus doesn't condone sin, but if we've accepted His remedy for our sins and confess (1 John 1:9) He chooses to leave it alone. He's done that for us because we asked Him, and now He asks us to do likewise for each other.

When we say the sinner's prayer, we're admitting that we can never meet God's requirements and need someone to intercede for us.  We ask the Lord Jesus to intercede and be our Savior.  He agrees to do this, not because we promise never to sin again, but because we admit we can't stop sinning." (Jack Kelley)

And that is the rub.  This is a view of the height from which we have fallen.  When we, as a race through Adam and Eve, disobeyed God, sin did not only enter into humanity and creation - it became our natural tendency.  We gravitated toward and still gravitate toward things that would feed our sinful nature.  Our normal operating procedure does not include God or His ways. 

"All of us are living in deliberate and open sin because in each human life there is observable behavior that violates God's word and is knowingly and willfully repeated.  It's not that we discover one sin in our behavior and root it out only to be made aware of another.  We deliberately repeat the same sinful behavior over and over.  If we could progressively root out and eliminate the sins in our lives we could eventually stop sinning and wouldn't need a savior.  Somehow we've come to believe that repent means to stop doing something, and if we don't stop doing it, then we haven't repented and therefore don't qualify for forgiveness. If that's true and the required salvation sequence is to repent and be saved, then none of us is saved, because none of us has stopped sinning." (Jack Kelley)

In the Old Testament, God reached out to humanity with rules, regulations, and guidelines to follow for their benefit.  In the New Testament, God in the flesh, as a lowly servant, is displayed and exemplifies the life to follow and teaches how to live, promising that once He leaves He will send the Comforter, the one whom will lead you, guide you, and direct you in all truth - the Holy Spirit.  The next manifestation and extension of His reach will be in the Millennium from His throne.  Still, because of our "faulty wiring", their will be those, making it through the Tribulation Period, who reject the rule of King Jesus.  Jack Kelley states this same thought as follows -

"In the Old Testament the emphasis was on obedience. The principle was behave or you won't be rewarded. And even with the threat of eternal punishment people still couldn't be good enough for God. In the New Testament the emphasis is on faith. Now the principle is behave because you will be rewarded and people still can't be good enough. In the Millennium the emphasis will be on experience. The principle then will be behave because you are being rewarded. Satan will be bound, God will live among His people and rule the world, the curse will be removed, and a Utopian life will be at hand. All of man's excuses for sinning will be gone. But at the end of that age, the people that God hasn't supernaturally perfected will rebel against Him. The underlying message of the whole Bible is that there is no circumstance in which mankind can achieve the standard God requires. Living in sin is a state of being, not just a state of rebellion. That's why we need a Savior."

Again, a great example of how to walk in forgiveness is to observe the awesomeness of Romans 5:8 - "But God demonstrates His own love for us in this:  while we were still sinners, Christ died for us."  If we could all draw an attitude out of this action by Christ of "while our brothers and sisters are still sinners and doing us wrong we will choose to forgive them" I think that would go a long way in all the relationships we hold, especially our relationship with God.

" a parable from Luke 7:41-43. Two men owed money to a certain money lender. One owed 2 years pay and the other owed 2 months. Neither could pay so the money lender canceled both debts. Completing the story, the Lord asked, "Which one will love the money lender most?"  Simon the Pharisee answered, "I suppose the one who had the bigger debt canceled." Good answer. He who has been forgiven much, loves much. Have we been forgiven much? "As I have loved you," the Lord said, "You must love one another" (John 13:34, 15:12 and 9 other places). He could just as easily have said, “As I have forgiven you, you must forgive one another." (Jack Kelley)

Do you want good health?  Favor?  Do you desire to be in the middle of God's will, executing His plan for your life?  If you seek these and more in your life but are not receiving quality feedback (i.e. audible voice, writings on the wall, etc..), one area of your life to start looking at is forgiveness.  Is there anyone whom I have not forgiven?  Freedom, restored relationship(s), and many other benefits are waiting after you effectively deal with that question.  No matter whether the offender has sought our forgiveness or not, forgiveness is encouraged (Ro.12:17-21).  This sets your house/heart in order and frees you from the bondage of never hearing an apology.  Forgiveness, a commanded lifestyle not a suggestion.