Philemon

For perhaps he departed for a while for this purpose, that you might receive him forever,  no longer as a slave but more than a slave—a beloved brother, especially to me but how much more to you, both in the flesh and in the Lord. vv.15-16

Read Philemon
This one chapter letter from Paul to Philemon, a wealthy man, about Philemon's runaway slave Onesimus.  Apparently Onesimus had run away from his owner and somehow met Paul who led him to Christ and now is a believer.  Now as a believer Onesimus wants to correct what he'd done wrong (whether by running away or also causing much financial hurt as we see Paul willing to pay his debt).  No doubt Paul is the one encouraging both parties, the offender and the offended, to make amends, especially now that they are both brothers in Christ.  Paul reminds Philemon to receive him forever as they will be eternally with God together as well, unlike unbelievers that will only be for a short time in this life.  
At times we've all been in one of their positions whether the one offended, the one who made the offense or the peacemaker between two parties.  Each one of those positions has some responsibility that isn't easy.  Onesimus had to humble himself and make right what he'd done wrong.  Philemon was to forgive and accept back a slave without punishment- canceling debt.  Paul was to do everything he could to bring unity between two brothers.  What position has been hardest for you in a certain situation?
If you were on an island and a phone dropped out of the sky and you could make three phone calls: one was to call someone to tell them I love you, one to tell them I forgive you, and one to say I'm sorry, to whom would those three phone calls be?