acts 1:22 Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection. - Free Bible Online

      22. Beginning from the baptism of John--by whom our Lord was not only Himself baptized, but first officially announced and introduced to his own disciples.
      unto that same day when he was taken up from us, must one be ordained to be a witness with us of his resurrection--How clearly is the primary office of the apostles here expressed: (1) to testify, from personal observation, to the one great fact of "the resurrection of the Lord Jesus"; (2) to show how this glorified His whole previous life, of which they were constant observers, and established His divine claims.

JFB.