Paul wants Philemon to receive Onesimus not merely as a returning servant but as a brother in Christ. Paul says Onesimus is already a beloved brother "specially to me." The question presses Philemon to see that he should be dearer still to him. Barnes gives reasons: Onesimus had been part of Philemon's own household, he would return as a penitent, and he had come back of his own will. Gill explains that the two phrases name two bonds: "in the flesh" (the earthly relationship of household and service) and "in the Lord" (as a fellow believer), making Onesimus doubly dear.

Paul does not wait for an answer; he turns the question into a request: "If thou count me therefore a partner, receive him as myself" (Philemon 1:17). He offers to cover any loss: "If he hath wronged thee, or oweth thee ought, put that on mine account" (Philemon 1:18), and adds in his own hand, "I Paul have written it with mine own hand, I will repay it" (Philemon 1:19). He closes "knowing that thou wilt also do more than I say" (Philemon 1:21). Philemon's reply is not recorded.

Onesimus had been Philemon's servant. The Greek word is doulos, a servant or slave; the ESV says "bondservant." Barnes cautions that the word "denotes servant of any kind" and does not by itself prove Onesimus was a slave. Paul says Onesimus "departed for a season" (Philemon 1:15) and may have "wronged" Philemon or owed him something (Philemon 1:18). He came to faith while Paul was in chains: "whom I have begotten in my bonds" (Philemon 1:10). Colossians 4:9 also calls him "a faithful and beloved brother, who is one of you." Barnes notes that "in the flesh" can refer to "any relation which may exist pertaining to the present world," including household or service, as distinct from the bond formed by faith.

The gospel did not erase the earthly relationship between Philemon and Onesimus, but it changed its center. Onesimus is now to be received "not now as a servant, but above a servant, a brother beloved." Matthew Henry writes, "There is a spiritual brotherhood between all true believers, however distinguished in civil and outward respects." The same grace that made Paul call Onesimus "my son" (Philemon 1:10) now asks Philemon to call him brother.

Paul's way of asking also reflects God's grace. He could have commanded, but "for love's sake I rather beseech thee" (Philemon 1:8-9), so that Philemon's kindness "should not be as it were of necessity, but willingly" (Philemon 1:14). And Paul stands in the gap, offering to pay what Onesimus owes (Philemon 1:18-19). Matthew Henry says that, by way of allusion, this may illustrate Christ's undertaking for us, who wronged God and whose debt Christ takes on Himself.