“On taking leave of them,
‘I will return
To you again,
Then he set sail
ἀλλὰ ἀποταξάμενος καὶ εἰπών Πάλιν ἀνακάμψω πρὸς ὑμᾶς τοῦ Θεοῦ θέλοντος, ἀνήχθη ἀπὸ τῆς Ἐφέσου,
The author of Acts indicated that on taking leave of them (ἀλλὰ ἀποταξάμενος), Paul said (καὶ εἰπών) that he would return to them again (Πάλιν ἀνακάμψω πρὸς ὑμᾶς), if God willed it (τοῦ Θεοῦ θέλοντος). Then he set sail (ἀνήχθη) from Ephesus (ἀπὸ τῆς Ἐφέσου). So, General MacArthur (1880-1964) did not make up the saying, “I shall return.” Paul used it here, with the phrase that is now commonplace, “God willing”. Paul would return to Ephesus in the next chapter on his third missionary trip. Thus, he sailed away from Ephesus towards Syria. Some Orthodox manuscripts indicated that Paul said “I must at all costs keep the approaching festival in Jerusalem (Δεῖ με πάντως τὴν ἑορτὴν τὴν ἐρχομένην ποιῆσαι εἰς Ἱεροσόλυμα).” That would make sense why he was not staying and maybe it had some connection to his vow. Have you ever said that you would return to some place?