Acts 1:8

But ye shall receive power. — The use of the same English noun for two different Greek words is misleading, but if “authority” be used in Acts 1:7 then “power” is an adequate rendering here. The consciousness of a new faculty of thought and speech would be to them a proof that the promise of the Kingdom had not failed.

Ye shall be witnesses unto me. — The words, which are apparently identical with those of Luke 24:48, strike the key-note of the whole book. Those which follow correspond to the great divisions of the Acts — Jerusalem, Acts 1:7; Judæa, 9:32, 12:19; Samaria, 8; and the rest of the book as opening the wider record of the witness borne “to the uttermost parts of the earth.” And this witness was two-fold: (1) of the works, the teachings, and, above all, of the Resurrection of Jesus; (2) of the purpose of the Father as revealed in the Son. The witness was to be, in language which, though technical, is yet the truest expression of the fact, at once historical and dogmatic.