A.T. Robertson Commentary Romans 16:13

"Salute Rufus the chosen in the Lord, and his mother and mine." — Romans 16:13 (ASV)

Rufus (Ρουφον). A very common slave name, possibly the Rufus of Mr 15:21. The word means "red."

The chosen (τον εκλεκτον). Not "the elect," but "the select."

And mine (κα εμου). Paul's appreciation of her maternal care once, not his real mother.