“…yet for love’s sake I rather appeal to you—being such a one as Paul, the aged, and now also a prisoner of Jesus Christ…”
being such a one as Paul, the aged,
Paul appeals to Philemon’s love on the basis of his age and situation as a prisoner – “such a one.” Older men could appeal to others with authority based on their age as a veteran in the cause of Christ. Older men were considered wise, and authority came from wisdom in the first century.
and now also a prisoner of Jesus Christ
Paul’s mention of his imprisonment is an appeal to Philemon to release Onesimus to help Paul in prison.
Respect for those mature in Christ is to the benefit of all who draw on their wisdom.
We do not respect troubadours for the cause of Christ like we should in our day. This is to our own loss.