A second purpose clause, so that any favor you do will be spontaneous and not forced, focuses the second part of Paul's explanation of Onesimus's usefulness to Philemon, and why his manumission (that is, the specific favor asked of Philemon) makes good sense. Why is Paul concerned that Philemon not be pressured into this decision? Surely Paul understands that Philemon may perceive him as exploiting their relationship to Onesimus's unfair advantage. Under such circumstances, his granting Paul's favor would be a hollow triumph and might even create bitterness between them. Sharply put, Paul here imagines a situation where his explicit appeal (manumission) is granted, but its implicit objective (reconciliation) is not accomplished. Paul's solution to this potential problem is to maintain Philemon's honor: the condition for the favor is that it be spontaneous and not forced; it must be an act of worship, freely offered to God (see O'Brien 1982:294-95).
In light of his concern for Philemon's honor, Paul's anticipation of the spiritual aftermath of Onesimus's manumission transforms the conventional perceptions of the relationship between a manumitted slave and his former master. Yet even before describing this new perception in verses 16 and 17, Paul mentions that Philemon's choice must be pressure-free and made in the awareness that his separation from Onesimus was short-term and not permanent (v. 15). While the meaning of the phrase he was separated from you remains contested among scholars, many now take it as a reference to the outworking of God's will rather than to Onesimus's fugitive status. The verbal voice is passive, implying that something or someone besides Onesimus is responsible for Onesimus's action. (O'Brien calls this a "divine passive" because it suggests the working out of God's will; 1982:295.) Further, Paul couples this phrase with the adverb perhaps (tacha), which is sometimes used in Jewish literature to introduce a theological exposition. For Paul, Onesimus's departure provides the setting for the work of God. Thus, Chrysostom's suggestive comparison of this text with the Old Testament Joseph story about divine providence (Gen 45:4-8; 50:15-21) seems quite right to me (see O'Brien 1982:295; Wright 1986:184-85): in both cases, God's redemptive purposes are achieved by the act of freeing a slave.
Given the importance of allusions to Old Testament types and texts in Paul's writings (see Hays 1988), Paul may have the Joseph story in mind as he writes his appeal to Philemon. That is, Paul recognizes Onesimus to be a type of the biblical Joseph. The relationship between the two may well suggest Paul's principal theological conviction in this case: God's good intentions for people are often worked out in the redemptive consequences of choices that free brothers make about slave brothers. Of course, in Joseph's story a bad choice (brothers' selling another brother into slavery) results in a good end because of divine intervention. In this case, Philemon's good choice (a "brother" manumitting another "brother" from slavery) would result in a similar end. From God's perspective, then, Philemon's favorable decision, which has been shown to make sense in light of Onesimus's past usefulness to him, would make even more sense when he considers the prospect of a redemptive result.
The intriguing comparison between for a little while and for good (aionion, literally "for an eternity") refers less to a changed social status (although see Harris 1991:266) than to the eternal destiny of both brothers, Philemon and Onesimus, who will share together the salvation of God (so O'Brien 1982:296). Paul's point is not that our decisions about social conventions bear witness to our convictions about God; rather, our convictions about God ought to prompt our decisions about the social order. Because Philemon trusts that God purposes good ends for God's people, Paul trusts that he will make a natural, free decision about Onesimus that will result in good.
Curiously, Wright does nothing with his interesting suggestion that Paul's use of aionion is an allusion to the teaching on Hebrew slaves found in Exodus 21 (1982:185, n. 1; see also Moule 1968:156). According to the legal code in Torah, the slave who rejected his sabbath manumission in order to stay with his master (see Ex 21:1-5) was first "brought" by the master to God as the condition for "lifelong" (literally "eternal") service (see Ex 21:6). In the Old Testament, God and eternity together frame a central tenet: whatever God's people consecrate to their eternal God in worship must then be embodied in their ongoing life together. I would argue that this is Paul's point here: Philemon is expected to make decisions toward his slave that embody his worship of God.
The results of Philemon's act of worship in manumitting Onesimus are twofold: (1) Onesimus is no longer a slave but a brother (v. 16), and (2) Onesimus is no longer a slave but a "partner" (v. 17). In both senses of their new relationship as brothers and partners in Christ, Onesimus acquires new responsibilities of spiritual usefulness to Philemon.
Some scholars do not think Paul envisions Onesimus's manumission from slavery, since no longer as a slave refers to his spiritual but not social status. While I agree that Paul chooses his words carefully, I do not agree that he makes a formal distinction between the social and spiritual realms so that the two cannot be fully integrated in Christ (see commentary on Col 1:15-20 and 3:22—4:1). The phrase makes a rhetorical point: Paul does not presume Onesimus's emancipation because such a decision is Philemon's to make freely, so the presumption would contradict Paul's earlier statement (v. 14).
Further, to contend that Philemon can make perceptual but not substantial changes in his relationship with Onesimus fails to integrate "seeing" with "doing" in the new creation. If Philemon decides to "see" Onesimus as a dear brother (compare this with Paul's greeting of Philemon in verse 1, "dear friend"), then his decision must be to emancipate him. Paul's additional phrase he is very dear to me but even dearer to you recalls his earlier expression of love for Onesimus as his "son" (v. 10). If both Philemon and Onesimus are Paul's spiritual sons, then they are indeed brothers in the Lord.
The fundamental shift of Onesimus's social status from "slave" to "dear brother" is repeated in the phrase both as a man and as a brother in the Lord. Again, Paul does not suppose that the social (as a man, literally "in the flesh") and the spiritual (as a brother) can be kept as two disjointed spheres of human existence. While God's creation includes both the visible and the invisible, they are integrated and held together by the one Lord. Thus, the spiritual well-being of the congregation will always be demonstrated publicly by the well-being of its social relationships (see commentary on Col 1:3-12; 3:1-11; 3:12-17). Harris's interpretation, so common among evangelicals, that Paul is speaking of a change of attitude rather than a change of social relationship—so that Onesimus will resume his position as a household slave, as before his conversion (Harris 1991:268)—fails to observe the calculus of Paul's gospel. In fact, Paul's letter to Philemon clarifies and extends the ethical implications of the gospel set forth in the household code of his letter to the Colossians (3:22—4:1). The book of Philemon's moral vision is that social hierarchies, such as the one between a powerful owner and his powerless slave, are dismantled in Christ. The presence of koinonia within a society of classes, hitherto divided between those who have power and value and those who do not, gives public testimony to the empowering grace of God.