The Apostle Paul
Romans 16:5ESV·traditional attribution

Greet also the church in their house. Greet my beloved Epaenetus, who was the first convert to Christ in Asia.

John Calvin Reformed @genevareformer

5. Who is the first-fruit, etc. This is an allusion to the rites of the law; for as men are sanctified to God by faith, they who first offer themselves are fitly called the first-fruit. Whosoever then is called first in time to the faith, Paul allows him the prerogative of honor: yet he retains this eminence only when the end corresponds with the beginning.

Matthew Henry Presbyterian @wholebiblehenry

Such remembrances as these are usual in letters between friends; and yet Paul, by the savouriness of his expressions, sanctifies these common compliments. I. Here is the recommendation of a friend, by whom (as some think) this epistle was sent - one Phebe, Rom 16:1, Rom 16:2.

Commenting on Romans 16:1-16

John Gill Reformed Baptist @doctorgill

Likewise greet the church that is in their house,.... Which was either their own family, which might be somewhat large, and consisting entirely or chiefly of religious persons; for when they were in other places they had a church in their house as well as Rome; see Co1 16:19; or the saints at Rome, who used to meet privately at their house, and pray and...