Okay, so the plan is to whip up a brief post here and there and maybe even queue up a few at a time. Can I do that? Can I be brief?
Waking up this morning [now a couple of days ago] the question nudged at me: What is the earliest evidence we have in the Church of prayers of living Christians for those Christian brothers and sisters who have passed over into death? So rolling out of bed, before I’d even had my coffee, in an uncaffeinated stupor, I set about to find out. That’s how you know it’s the Holy Spirit working — that same Spirit that raised Christ from the dead, quickening my mortal body to do good works, though the mind be absent.
May the Lord grant mercy to the household of Onesiphorus, for he often refreshed me; he was not ashamed of my chains, but when he arrived in Rome he searched for me eagerly and found me — may the Lord grant him to find mercy from the Lord on that Day — and you well know all the service he rendered at Ephesus.
Onesiphorus, it should be clear, is dead. St. Paul speaks of him in the past (aorist) tense. He was not ashamed of Paul’s chains, a simple action in the past, not an ongoing one. Since Paul is still in chains (2 Timothy 2:9), and Onesiphorus’s not-being-ashamed is not ongoing, and he is not still refreshing Paul, it is evident that Onesiphorus is no longer living. Paul first asks God’s mercy for the household of Onesiphorus, not Onesiphorus himself. Regarding Onesiphorus, Paul prays that he find mercy from the Lord on that Day. On that Day (this is the capitalization shown in the RSVCE and ESV) has a very clear eschatological connotation: this is the last day, the Day of the Lord. Paul is asking for God’s mercy on Onesiphorus before the throne of Judgment.
Now, against Protestant objections: why would Paul ask for God’s mercy on someone before the Judgment Seat, when that person was still living? Whoever says, “May God have mercy on your soul — that is, when you die”? Onesiphorus is quite dead. And the fact that after his passing, Paul still prays for God’s mercy on him is a clear, scriptural indication that in the view of Paul, the Apostle, the inspired writer, such prayers for the dead are beneficial. As Scripture says elsewhere (and as Protestants conveniently reject), “it was a holy and pious thought [to make] atonement for the dead, that they might be delivered from their sin.” (2 Maccabees 12:45, RSVCE)