Acts 21:23

εἰσὶν ἡμῖν, cf. Acts 18:10. The four men certainly seem to have been members of the Church at Jerusalem, i.e., Jewish Christians. εὐχὴν ἔχοντες : a temporary Nazirite vow, Numbers 6:1 ff. The length of time was optional, but thirty days seems to have been the shortest time, Jos., B.J., ii., 15, 1. ἐφʼ ἑαυτῶν, see critical note, the Nazirite vow lies upon them as an unfulfilled obligation. If we read ἀφʼ it would mean him to affirm that the vow had been taken by them of their own will, on their own initiation, cf. Luke 12:57; 2 Corinthians 3:5; John 5:19; John 5:30, etc., see further Grimm-Thayer, sub v. ἀπό, ii., 2 d, aa; and Rendall, in loco. Blass however renders ἐφʼ “quia votum in se receperunt,” so that it is difficult to distinguish very definitely.