Final answer:
The Colossian believers heard Paul favorably mention Onesimus, the runaway slave, but not Philemon his master.
Step-by-step explanation:
In the New Testament of the Bible, specifically in Paul's letter to Philemon, the character Onesimus takes a central role in a narrative unfolding in Philemon's house. As the Colossian believers gather to hear Paul's letter, they witness a profound moment as Paul positively acknowledges Onesimus, the runaway slave, without direct mention of Philemon, his master. This subtle yet impactful omission underscores themes of reconciliation, forgiveness, and equality, inviting readers to reflect on the transformative power of Christian principles in interpersonal relationships, particularly in the context of societal norms and expectations during the time.