There salute thee Epaphras - The same persons who are here mentioned as greeting Philemon, are mentioned in the close of the Epistle to the Colossians - furnishing a high degree of evidence that Philemon resided at Colosse. Epaphras was a member of the church there; the notes at Colossians 4:12.
My fellow-prisoner in Christ Jesus - In the cause of Christ; Notes, Plm 1:1. The circumstance of his being a prisoner is not mentioned in the parallel place in the Epistle to the Colossians, but nothing is more probable.

Epaphras, my fellow prisoner - Epaphras was a Colossian, as we learn from Colossians 4:12 : Epaphras, who is one of you. But there is no account there of his being in prison, though the not mentioning of it does not necessarily imply that he was not. Some time or other he had suffered imprisonment for the truth of the Gospel; and on that account St. Paul might, in a general way, call him his fellow prisoner.

There salute thee Epaphras,.... Who was a Colossian, and minister of the church at Colosse, and so might be well known to Philemon, who seems to have been of the same place and church; see Colossians 1:7 his name is omitted in the Ethiopic version:
my fellow prisoner in Christ Jesus; this good man, and minister of Christ, might have been sent by the Colossians, as Epaphroditus was by the Philippians, to the apostle at Rome, to pay him a visit, and comfort and assist him under his afflictions; and staying and preaching the Gospel there, was committed to prison, or was laid in bonds, as the apostle was, and upon the same account; namely, for the sake of Christ, and his Gospel. For by this time Nero began to persecute the Christians, which he did in the better and more moderate part of his reign; for among several things for which he is commended by the historian (b), this is one,
""Afficti suppliciis Christiani, genus hominum superstitionis novae ac maleficae"; the Christians were punished, a sort of men of a new and bad religion:
and Epaphras being at Rome, when this persecution broke out, was taken up and put in prison, as were also Aristarchus, Colossians 4:10 and Timothy, Hebrews 13:23.
(b) Suetonius in Vita Neronis, c. 16.

Never have believers found more enjoyment of God, than when suffering together for him. Grace is the best wish for ourselves and others; with this the apostle begins and ends. All grace is from Christ; he purchased, and he bestows it. What need we more to make us happy, than to have the grace of our Lord Jesus Christ with our spirit? Let us do that now, which we should do at the last breath. Then men are ready to renounce the world, and to prefer the least portion of grace and faith before a kingdom.

The same persons send salutations in the accompanying Epistle, except that "Jesus Justus" is not mentioned here.
Epaphras, my fellow prisoner--He had been sent by the Colossian Church to inquire after, and minister to, Paul, and possibly was cast into prison by the Roman authorities on suspicion. However, he is not mentioned as a prisoner in Colossians 4:12, so that "fellow prisoner" here may mean merely one who was a faithful companion to Paul in his imprisonment, and by his society put himself in the position of a prisoner. So also "Aristarchus, my fellow prisoner," Colossians 4:10, may mean. Benson conjectures the meaning to be that on some former occasion these two were Paul's "fellow prisoners," not at the time.