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."
Cross References (ranked by relevance)
Acts 1:2
Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
Acts 4:33
And with great power gave the apostles witness of the resurrection of the Lord Jesus: and great grace was upon them all.
Hebrews 2:3
How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard him;
John 15:27
And ye also shall bear witness, because ye have been with me from the beginning.