4:19 Salute Prisca and Aquila. These tried friends, whom he first met in Corinth, afterwards in Ephesus, who returned also to Rome, were now again in Ephesus.
The household of Onesiphorus. See 2Ti 1:16. Some have thought that this form implies that Onesiphorus was dead, but that does not follow necessarily.
4:19-22 We need no more to make us happy, than to have the Lord Jesus Christ with our spirits; for in him all spiritual blessings are summed up. It is the best prayer we can offer for our friends, that the Lord Jesus Christ may be with their spirits, to sanctify and save them, and at last to receive them to himself. Many who believed as Paul, are now before the throne, giving glory to their Lord: may we be followers of them.
