Again Paul repeats I make a request; it is on behalf of Onesimus, whom he calls “my child” (Revised Standard Version). In order to make clear that this is a spiritual relationship, Good News Translation has my own son in Christ and spiritual father (compare Barclay “I became his father in the faith”). While Paul was in prison, he was able to lead Onesimus to accept the Christian faith. In 1 Cor 4.15, Paul also uses the figure of “begetting” people as Christian converts.
I make a request is equivalent in some languages to “I ask you please.”
On behalf of Onesimus may be expressed in some instances as “concerning Onesimus,” but it is better to try to introduce Onesimus as the one who is going to benefit from such a request; therefore, “I ask you as a help to Onesimus.”
The figurative expression in the clause who is my own son must be restructured as a simile in some languages, for example, “who is, as it were, my own son” or “who has become, so to speak, my own son.” The phrase in Christ may then be combined as “who as now a fellow believer in Christ is, as it were, my own son.”
I have become his spiritual father must also be expressed in some languages as a simile, for example, “I have become, so to speak, his father.” What is expressed in the Good News Translation as spiritual also suggests the figurative meaning of “father,” but it is difficult in a number of languages to find a ready equivalent of spiritual. Therefore, the introduction of an expression such as “so to speak” or “as it were” is perhaps the best way of qualifying this significant metaphor. In some cases, one may say “I have become his father in that he is now a part of the family of believers,” but such an expression would seem to be too expanded.
On the basis of the relation of the accusative form of Onesimus in Greek to the verb “I begot,” John Knox infers that the name Onesimus is the slave’s Christian name given him by Paul.
Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on Paul’s Letter to Philemon. (UBS Handbook Series). New York: UBS, 1977. For this and other handbooks for translators see here .