But when two years were fulfilled (dietias de plērōtheisēs). Genitive absolute first aorist passive of plēroō, common verb to fill full. Dietia, late word in lxx and Philo, common in the papyri, in N.T. only here and Act 28:30. Compound of dia, two (duo, dis) and etos, year. So Paul lingered on in prison in Caesarea, waiting for the second hearing under Felix which never came. Caesarea now became the compulsory headquarters of Paul for two years. With all his travels Paul spent several years each at Tarsus, Antioch, Corinth, Ephesus, though not as a prisoner unless that was true part of the time at Ephesus for which there is some evidence though not of a convincing kind. We do not know that Luke remained in Caesarea all this time. In all probability he came and went with frequent visits with Philip the Evangelist. It was probably during this period that Luke secured the material for his Gospel and wrote part or all of it before going to Rome. He had ample opportunity to examine the eyewitnesses who heard Jesus and the first attempts at writing including the Gospel of Mark (Luk 1:1-4).
Was succeeded by (elaben diadochon). Literally, “received as successor.” Diadochos is an old word from diadechomai, to receive in succession (dia, duo, two) and occurs here alone in the N.T. Deissmann (Bible Studies, p. 115) gives papyri examples where hoi diadochoi means “higher officials at the court of the Ptolemies,” probably “deputies,” a usage growing out of the “successors” of Alexander the Great (Moulton and Milligan’s Vocabulary), though here the original notion of “successor” occurs (cf. Josephus, Ant. XX. 8, 9). Luke does not tell why Felix “received” a successor. The explanation is that during these two years the Jews and the Gentiles had an open fight in the market-place in Caesarea. Felix put the soldiers on the mob and many Jews were killed. The Jews made formal complaint to the Emperor with the result that Felix was recalled and Porcius Festus sent in his stead.
Porcius Festus (Porkion Phēston). We know very little about this man. He is usually considered a worthier man than Felix, but Paul fared no better at his hands and he exhibits the same insincerity and eagerness to please the Jews. Josephus (Ant. XX. 8, 9) says that “Porcius Festus was sent as a successor to Felix.” The precise year when this change occurred is not clear. Albinus succeeded Festus by a.d. 62, so that it is probable that Festus came a.d. 58 (or 59). Death cut short his career in a couple of years though he did more than Felix to rid the country of robbers and sicarii. Some scholars argue for an earlier date for the recall of Felix. Nero became Emperor Oct. 13, a.d. 54. Poppaea, his Jewish mistress and finally wife, may have had something to do with the recall of Felix at the request of the Jews.
Desiring to gain favour with the Jews (thelōn te charita katathesthai tois Ioudaiois). Reason for his conduct. Note second aorist (ingressive) middle infinitive katathesthai from katatithēmi, old verb to place down, to make a deposit, to deposit a favour with, to do something to win favour. Only here and Act 25:9 in N.T., though in some MSS. in Mar 15:46. It is a banking figure.
Left Paul in bonds (katelipe ton Paulon dedemenon). Effective aorist active indicative of kataleipō, to leave behind. Paul “in bonds” (dedemenon, perfect passive participle of deō, to bind) was the “deposit” (katathesthai) for their favour. Codex Bezae adds that Felix left Paul in custody “because of Drusilla” (dia Drousillan). She disliked Paul as much as Herodias did John the Baptist. So Pilate surrendered to the Jews about the death of Jesus when they threatened to report him to Caesar. Some critics would date the third group of Paul’s Epistles (Philippians, Philemon, Colossians, Ephesians) to the imprisonment here in Caesarea, some even to one in Ephesus. But the arguments for either of these two views are more specious than convincing. Furneaux would even put 2Ti 4:9-22 here in spite of the flat contradiction with Act 21:29 about Trophimus being in Jerusalem instead of Miletus (2Ti 4:20), a “mistake” which he attributes to Luke! That sort of criticism can prove anything.