John Calvin Commentary Philemon 1:2

"and to Apphia our sister, and to Archippus our fellow-soldier, and to the church in thy house:" — Philemon 1:2 (ASV)

And to Archippus our fellow-soldier. He next adds "Archippus," who also appears to have been a minister of the Church; at least, this seems probable if he is the same person mentioned toward the end of the Epistle to the Colossians (Colossians 4:17), which is not at all improbable. For the designation, "fellow-soldier," which he gives to this latter individual, especially belongs to ministers.

Although the condition of a soldier belongs to all Christians universally, teachers may be regarded as standard-bearers in the warfare. Therefore, they ought to be more ready than all others to fight, and Satan usually causes them greater trouble. It is also possible that Archippus attended and shared in some contests Paul maintained; indeed, this is the very word Paul uses whenever he mentions persecutions.

And to the Church which is in thy house. By using these terms, he gives the highest praise to the family of Philemon. And certainly, it is no small praise for a householder that he manages his family in such a way that it becomes an image of the Church, and also fulfills the duty of a pastor within the walls of his own home. Nor should we forget to mention that this good man had a wife of similar character, for she, too, not without reason, is commended by Paul.