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. And doubtless it is no common honor when God chooses some for first-fruits: and there is in addition a greater and an ampler trial of faith, through a longer space of time, provided they who have first begun are not wearied in their course. [1]

Footnotes

1 - Epaenetus, who is here called the first-fruit of Achaia, may have been off the family of Stephanas, who is said to have been the first-fruit in 1-Corinthians 16:15. But the majority of copies has Asia, Asias, here, instead of Achaia, Achaias. By Asia is often meant Asia Minor, and so here, no doubt, if it be the right reading. -- Ed.

The church that is in their house - Aquila and Priscilla are mentioned Acts 18:26 as having received "Apollos" into their family, to instruct him more perfectly. The church in their house is also mentioned 1-Corinthians 16:19. This may mean either the church that was accustomed to assemble for worship at their hospitable mansion; or it may mean their own family with their guests, regarded as a "church." In those times Christians had no houses erected for public worship, and were therefore compelled to meet in their private dwellings.
Salute - The same word before translated "greet."
Who is the first-fruits - One who first embraced Christianity under my preaching in Achaia. The "first-fruits" were a small part of the harvest, which was first gathered and offered to the Lord; Exodus 22:29; Exodus 23:16; Leviticus 2:12; Deuteronomy 18:4. In allusion to this, Paul calls Epenetus the first-fruits of the great spiritual harvest which had been gathered in Achaia.
Achaia - See the note at Romans 15:26. This name and those which follow are chiefly "Greek," but we know little of the persons mentioned, except what is here recorded.

The Church that is in their house - In these primitive times no such places existed as those which we now term churches; the word always signifying the congregation or assembly of believers, and not the place they assembled in. See the term defined at the end of the notes, Matthew 16:28 (note).
Epenetus - the first fruits of Achaia - In 1-Corinthians 16:15, the house or family of Stephanas is said to be the first fruits of Achaia: how then can it be said here, that Epenetus was the first fruits, or first person who had received the Gospel in that district? Ans. - Epenetus might have been one of the family of Stephanas; for it is not said that Stephanas was the first fruits, but his house or family; and there can be no impropriety in supposing that one of that house or family was called Epenetus; and that this person, being the only one of the family now at Rome, might be mentioned as the first fruits of Achaia; that is, one of that family which first received the Gospel in that country. This would rationally account for the apparent difficulty, were we sure that Αχαιας, of Achaia, was the true reading: but this is more than doubtful, for Ασιας, of Asia, is the reading of ABCDEFG, some others; the Coptic, Ethiopic, Armenian, Vulgate, and Itala; and some of the chief of the fathers. On this evidence Griesbach has admitted it into the text. Yet the other reading is sufficiently natural, for the reasons already assigned.

Likewise [greet] the (b) church that is in their house. Salute my wellbeloved Epaenetus, who is the (c) firstfruits of Achaia unto Christ.
(b) The company of the faithful, for in so great a city as that was, there were different companies.
(c) For he was the first of Achaia that believed in Christ: and this type of speech is an allusion to the ceremonies of the law.

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 1-Corinthians 16:19; or the saints at Rome, who used to meet privately at their house, and pray and sing praises together, speak to one another of the things of God, and build up one another in their most faith; and from their gathering together in the name of Christ, and for the worship of him, and among whom his presence, according to his promise, was, they are called a church, or an assembly of Christians.
Salute my well beloved Epaenetus; for though all the saints were beloved by the apostle, yet there were some, as this good man, for whom he might have, on some account or another, a particular affection; as our Lord, as man, had for his disciple John, though he loved all his disciples. There is one of this name, said to be one of the seventy disciples, and bishop of Carthage; See Gill on Luke 10:1.
Who is the firstfruits of Achaia unto Christ; that is, either he was one of the chief and principal for gifts and grace, or one of the first that was converted to Christ in those parts: the allusion is to the firstfruits under the law, which were offered unto the Lord, and were pledges of, and sanctified the rest. The Vulgate Latin, instead of Achaia, reads "Asia": and so it is read in the Alexandrian copy, and others: the reason of this different reading seems to be, because the house of Stephanas are said to be the firstfruits of Achaia, 1-Corinthians 16:15. But this hinders not but that Epaenetus might be so too, for he might be one of the family of Stephanas, who was now removed to Rome. If he was a Jew, his Jewish name might be Judah, the same with Epaenetus, in Greek.

Likewise the church that is in their house--The Christian assembly that statedly met there for worship. "From his occupation as tent-maker, he had probably better accommodations for the meetings of the church than most other Christians" [HODGE]. Probably this devoted couple had written to the apostle such an account of the stated meetings at their house, as made him feel at home with them, and include them in this salutation, which doubtless would be read at their meetings with peculiar interest.
Salute my well beloved EpÃ&brvbr;netus, who is the first-fruits--that is, the first convert
of Achaia unto Christ--The true reading here, as appears by the manuscripts, is, "the first-fruits of Asia unto Christ"--that is, Proconsular Asia (see Acts 16:6). In 1-Corinthians 16:15 it is said that "the household of Stephanas was the first-fruit of Achaia"; and though if EpÃ&brvbr;netus was one of that family, the two statements might be reconciled according to the received text, there is no need to resort to this supposition, as that text is in this instance without authority. EpÃ&brvbr;netus, as the first believer in that region called Proconsular Asia, was dear to the apostle. (See Hosea 9:10; Micah 7:1). None of the names mentioned from Romans 16:5-15 are otherwise known. One wonders at the number of them, considering that the writer had never been at Rome. But as Rome was then the center of the civilized world, to and from which journeys were continually taken to the remotest parts, there is no great difficulty in supposing that so active a travelling missionary as Paul would, in course of time, make the acquaintance of a considerable number of the Christians then residing at Rome.

Salute the church that is in their house - Aquila had been driven from Rome in the reign of Claudius, but was now returned, and performed the same part there which Caius did at Corinth, Romans 16:23. Where any Christian had a large house, there they all assembled together though as yet the Christians at Rome had neither bishops nor deacons. So far were they from any shadow of papal power. Nay, there does not appear to have been then in the whole city any more than one of these domestic churches. Otherwise there can be no doubt but St. Paul would have saluted them also. Epenetus - Although the apostle had never been at Rome, yet had he many acquaintance there. But here is no mention of Linus or Cemens; whence it appears, they did not come to Rome till after this. The firstfruits of Asia - The first convert in the proconsular Asia.