The New John Gill Exposition of the Entire Bible1 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;
(See Gill on 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.