And he said, The God of our fathers hath chosen thee, that thou shouldest know his will, and see that Just One, and shouldest hear the voice of his mouth.
And he said, The God of our fathers hath chosen thee - studiously linking the new economy upon the old, as but the sequel of it, both having one glorious Author.
That thou shouldest know his will, and see that ('the') Just One (cf. Acts 3:14; Acts 7:52 ),
And shouldest hear the voice of his mouth - in order to place him on a level with the other apostles who had "seen the (Risen) Lord."