The answer is: Philemon

A little book, only 25 verses, found just before Hebrews.

Philemon is often overshadowed by Paul's major letters, yet it's a tiny gem that opens windows into early Christian relationships and the complexities of personal dynamics amidst social structures like slavery. Written with warmth and urgency, Paul pens this short letter to Philemon, revealing both a personal and social dilemma of the early church era.

The story goes beyond the bond between a master and his runaway slave, Onesimus. As Onesimus meets Paul, he transforms from an unprofitable slave into a beloved brother in Christ. Isn’t it fascinating how Paul challenges the traditional social norms by promoting the idea of equality in faith—that in Christ, there’s no distinction between a slave and a free man? This was radical thinking back then!

Interestingly, ancient slavery was quite different from contemporary perceptions. Many slaves had legal rights and could earn their freedom, turning the relationship between master and servant into something that could potentially be more humane. Paul's advocacy for Onesimus stands as a precursor to modern themes about liberty and social justice, which makes it relevant even today.

Also, in the spirit of entertaining insights, the name “Onesimus” translates to “useful” or “profit.” How poetic that by gaining freedom through faith, he became "useful" in a new, redemptive sense—a powerful hinge in the gears of early church life. What a wonderful illustration that transformation is possible for all, transforming the difficult filters of our societal roles into deeper connections of love and respect.