Acts 1:22

Beginning from the baptism of John - The words “beginning from” in the original refer to the Lord Jesus. The meaning may be thus expressed, “during all the time in which the Lord Jesus, beginning (his ministry) at the time when he was baptized by John, went in and out among us, until the time when he was taken up,” etc. From those who had during that time been the constant companions of the Lord Jesus must one be taken, who would thus be a witness of his whole ministry.

Must one be ordained - It is fit or proper that one should be ordained. The reason of this was, that Jesus had originally chosen the number twelve for this work, and as one of them had fallen, it was proper that the vacancy should be filled by some person equally qualified for the office. The reason why it was proper that he should be taken from the seventy disciples was, that they had been particularly distinguished by Jesus himself, and had been witnesses of most of his public life, Luke 10:1. The word “ordained” with us has a fixed and definite signification. It means to set apart to a sacred office with proper forms and solemnities, commonly by the imposition of hands. But this is not, of necessity, the meaning of this passage. The Greek word usually denoting “ordination” is not used here. The expression is literally, “must one be, or become, γενέσθαι genesthai, a witness with us of his resurrection.” The expression does not imply that he must be set apart in any particular manner, but simply that one should be designated or appointed for this specific purpose, to be a witness of the resurrection of Christ.