Last week I claimed that no one in the ancient world would have assumed that slaves and masters share the same humanity and that this made it unlikely that the phrase adelphoi en sarki (lit., “brothers in the flesh”) can mean “fellow humans.”
One might object, however, that this is precisely the burden of Paul’s letter—he’s urging Philemon to view Onesimus differently. Rather than seeing him as property or as less than human, Paul wants Philemon to welcome Onesimus and to treat him with the dignity due a fellow human and brother in the Lord.
Responding to this objection leads to a second reason why I think that it is unlikely that Paul means that they are fellow human beings.
While some commentators read vv. 15-16 as Paul urging Philemon to view Onesimus as adelphon en sarki, Paul’s statement simply cannot be regarded as an exhortation. If it were an exhortation on Paul’s part, the case for the phrase meaning “fellow human” would be strengthened. On such a view, Paul would be calling on Philemon to treat Onesimus in a way that runs against the grain of cultural assumptions.
But there isn’t an exhortation here. Paul is, rather, building on the already-established and plainly obvious fact that Philemon and Onesimus are adelphoi en sarki. He’s not trying to get Philemon to see this; he’s assuming that Philemon already knows it.
This is something that is plain to Philemon, Onesimus, and Paul. Consider again the form of Paul’s statement in vv. 15-16:
For perhaps because of this he was separated from you for a time, that you might receive him back forever, no longer as a slave but more than a slave, a beloved brother, exceedingly to me, but how much more to you, both in the flesh and in the Lord.
The first realm in which Philemon and Onesimus are brothers is recognized and already established—that is, “in the flesh.” It’s the second realm in which they’re brothers that is the new reality (“in the Lord”) and it is according to this reality that Paul is urging Philemon to act.
What has changed is that Philemon and Onesimus now participate in the “fellowship of faith” (v. 6), and Paul prays at the beginning of the letter that this reality may become effective for Philemon so that he will act in a way that is consistent with it.
Taking our first two considerations together makes it even more unlikely that Paul is indicating that Philemon and Onesimus are fellow humans. If this were Paul’s intention, then the effect of his statement would be to shame Philemon before the community (keep in mind the letter is addressed to Philemon and the church community [vv. 1-2]).
If slaves were not considered as sharing the full humanity of their masters, then Paul would be assuming something highly embarrassing to Philemon, putting him on the defensive, and provoking him to react negatively to Paul’s request. On the majority view, Paul would be subverting his own aims.
If everyone assumed that slaves and masters did not share the same humanity, Paul would not have worked from this notion as a starting point without risking the public shaming of Philemon. Their common humanity is a notion that Paul would need to work toward. It’s not something he could merely assume.