Verse 15. For thou shalt be his witness, etc. As an apostle to testify to all men that the Messiah has come, that he has died, that he has risen, and that he is the Saviour of the world.

Of what thou hast seen and heard. Of the remarkable proof which has been furnished you of the Divine mission and character of the Lord Jesus.

{d} "thou shalt" Ac 23:11; 16:16