Apostelgeschichte 1:21

all the time the Lord Jesus went in and out among us--in the close intimacies of a three years' public life.

The inspired historian begins his narrative of the Acts of the Apostles, I. With a reference to, and a brief recapitulation of, his gospel, or history of the life of Christ, inscribing this, as he had done that, to his friend Theophilus (Act 1:1, Act 1:2). II. With a summary of the proofs of Christ's resurrection, his conference with his disciples, and the instructions he gave them during the forty days, of his continuance on earth (Act 1:3-5). III. With a particular narrative of Christ's ascension into heaven, his disciples' discourse with him before he ascended, and the angels' discourse with them after he ascended (Act 1:6-11). IV. With a general idea of the embryo of the Christian church, and its state from Christ's ascension to the pouring out of the Spirit (Act 1:12-14). V. With a particular account of the filling up of the vacancy that was made in the sacred college by the death of Judas, by the electing of Matthias in his room (Act 1:15-26).

1:21-22 To qualify for nomination as an apostle, a man had to have been with the other apostles the entire time of Jesus’ public ministry, from the time he was baptized by John until his ascension.