G4961–συστρατιώτης–sustratiōtēs

But it seemed to me necessary to send to you Epaphroditus, my brother, who has taken part with me in the work and in the fight, and your servant, sent by you for help in my need;

συστρατιώτην sustratiōtēn “fellow soldier”

And to Apphia, our sister, and to Archippus, our brother in God's army, and to the church in your house:

συστρατιώτῃ sustratiōtē “fellow soldier”