Festus was sent by Nero as his successor; before him Paul, having pleaded his cause, was taken as a prisoner to Rome. Aristarchus was with him, whom in one of his Epistles he naturally calls his fellow-prisoner. And Luke also, who set down in writing the Acts of the Apostles, here brought his history to a close, noting that Paul spent two whole years in Rome at liberty and preached the word of God without hindrance.
Tradition holds that the apostle, having then made his defence, was again sent forth upon the ministry of preaching, and that on coming a second time to the same city he was perfected by martyrdom under Nero. During this imprisonment he composed the Second Epistle to Timothy, indicating at once both his earlier defence and his impending perfecting.
Receive, then, his own testimony to these things; he says: "At my first defence no one stood by me, but all forsook me (may it not be laid to their charge); yet the Lord stood by me and strengthened me, that through me the proclamation might be fully made, and that all the Gentiles might hear; and I was delivered out of the lion's mouth."
By these words he clearly shows that on the former occasion, in order that the proclamation made through him might be fulfilled, he was delivered out of the lion's mouth—calling Nero, it seems, by this name on account of his cruelty. He did not therefore go on to add anything like "He will deliver me out of the lion's mouth," for he saw in the Spirit that his end was now all but at hand.
Wherefore he says, adding to the words "and I was delivered out of the lion's mouth" this: "The Lord will deliver me from every evil work and will save me unto his heavenly kingdom"—signifying his immediate martyrdom, which he also foretells more plainly in the same writing, saying: "For I am already being poured out as a drink-offering, and the time of my departure is at hand."
Now in the second of his Epistles to Timothy he makes clear that only Luke was with him as he wrote, but at the former defence not even he. Whence it is reasonable that Luke brought the Acts of the Apostles down to that time, having narrated the history up to the point when he was with Paul.
It is indeed likely that, since at the beginning Nero was more mildly disposed, Paul's defence on behalf of his teaching was the more easily received; but when Nero advanced to lawless acts of daring, then, together with the rest, the measures against the apostles also were undertaken.