Philemon

So for this book we went through the four steps  (Observation>Historical Background>Interpretation>Application) for over 20 things in throughout the scripture, but I'm just going to flesh out for you the one that interested me the most.

I recommend you read through the book once before reading on.  It's only 25 verses, but everything will make a little more sense if you have the context.

GENERAL IDEA+some HISTORICAL BACKGROUND:
So after reading through it, you can see that the letter is an appeal to Philemon from the Apostle Paul to accept back his slave Onesimus.  Onesimus had run away from Philemon (in Colossae) to Rome (where the majority of the population was made up of slaves or former slaves) and had met Paul while he was in prison there.  He had become a Christian through his relationship with Paul, who was now sending him back to Philemon, who was also a Christian.  Paul is asking Philemon to receive Onesimus back in love, as a brother, with no debt owed while the cultural standard said that Onesimus is Philemon's property and therefore he could do with him whatever he saw fit- which oftentimes in this situation was crucifixion.

OBSERVATION:
So we observed the repeated theme of close relationships...
Paul calls Timothy a brother (verse 1)
Philemon a beloved fellow worker (verse 1) and his brother (verse 7, 20)
Apphia a sister (verse 2)
Archippus a fellow soldier (verse 2)
Onesimus his child (verse 10) and his very heart (verse 12)
and calls Mark, Aristarchus, Demas and Luke his fellow workers (verse 23)

INTERPRETATION:
Why would Paul repeat this idea so often, and use it to refer to so many different people?
To communicate that when people receive Christ, they become a part of the same family.  They are closely connected to one another, no matter what their previous background.
Why might Philemon need to be reminded of this?
Culture would tell him that Onesimus is his property and he can do what he wants with him, but as a believer he ought to treat him as a brother.

APPLICATION:
Are there any timeless truths that we can take from this?
Yes, as Christians we ought to see all other Christians as family-regardless of social standing, race, gender, denomination, or how our culture tells us to receive them.
This whole point of this letter is a call to reconciliation of a broken relationship and forgiveness. We can definitely apply these principles in our lives today.

Side note: In Acts 15:37-40, at the beginning of Paul's second missionary journey, we see that Mark and Paul parted ways over a sharp disagreement.  This letter is written after Paul's third missionary journey, so just the fact Mark is included in the list of people who sends greetings at the end of this letter proves that Paul has reconciled a broken relationship with another Christian-that he's willing to practice what he preaches.