1 Corinthians 16:8

But I will tarry at Ephesus till Pentecost. The feast of weeks, or of harvest, which was fifty days from the passover;

Acts 2:1 which though abrogated at the death of Christ, was observed by the Jews, and is mentioned by the apostle, not as a festival that the Christians were obliged to regard, or did regard, but as pointing out the time he intended to stay at Ephesus: and we elsewhere read, that he was greatly desirous of being at Jerusalem on the day of Pentecost, Acts 20:16 not to keep it, but because there would then be abundance of people from all parts there, to whom he should have an opportunity of preaching the Gospel.