Let's pretend that we all are parents of not only blood-born children, but adopted kids as well. The adopted kids are paid for by us to have the right of ownership. The blood-born kids are continually bought through their life by provision until they realize this form of love and reciprocate. 

The kids are going to rebel, disobey and/or sin. Are you going to kick them out of the family and re-instate them after a probationary period? Of course not! Both blood-born and adopted kids are family - once and for all time. You are not going to go back and repay for the adopted or start over with your other children. So it is with God when we rebel, disobey or sin against Him.

In Matthew 6:14-15, Jesus said, "For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins."

Jesus is teaching The Way we should live to His Disciples then and now. This part of Christ's Way of Living -  if you do not forgive others their sins, your Father will not forgive your sins. - does not concern the believer's overall Salvation. Paul reminds us - "He did not enter by means of the blood of goats and calves; but he entered the Most Holy Place once for all by his own blood, thus obtaining eternal redemption." (Hebrews 9:12) His Redemption restored our relationship with Him and secured our destination with Him also.

The word "sins" in this passage comes from the Greek word paraptoma, meaning trespass or transgression. And the Lord is using this word in a knowing-way. Knowing that we, as believer's in Christ, will still sin. So, He requires us to be the the example now and forgive SO THAT afterwards when we ask Him of forgiveness, we are in the proper spirit to receive His forgiveness. Another excellent story that Jesus tells about this living out forgiveness is The Parable of the Unmerciful Servant found in Matthew 18:23-35. Forgiveness must be given before it can be granted. So, you are going to be forgiven, you just need to make sure you have forgiven all those who have grieved, transgressed and/or trespassed against you first.

Even though Christ has not died for them at this point in the narrative, He considers them part of His Family already. As their Rabbi, Lord and Most Senior Brother - Jesus re-emphasizes what was declared earlier in the Lord's Prayer, "forgive us our debts, as we also have forgiven our debtors." (Matt. 6:12) 

Notice something? We are still in His Family. He has not kicked us out for not forgiving others. Christ's forgiveness,  which is a blessing unto itself, is simply withheld. Other favors from His Hands might be withheld to move us in the direction of forgiving others SO THAT we will seek forgiveness in the right spirit. The forgiven know how to forgive and come humbly before their God for their forgiveness. Matthew 6:14-15 is about The Life We Live In Light Of Our Salvation.