Regarding Pentecost, some feel that the Bible records Jesus keeping it with the Jews, apparently in agreement as to the proper day, in Luke 4:16. This is the Sabbath on which Jesus, in His hometown, formally states the purpose of His ministry.
Luke does not say it is Pentecost, just that it is a Sabbath He customarily kept. The evidence derives from what He read from the Scriptures. According to the Jewish Encyclopedia, under the article "Triennial Cycle" (a three-year plan for the public reading of the Old Testament, attributed to Ezra), the portion of the Law to be read on Pentecost in the second year of the cycle (AD 28) is Exodus 20. The Pentecost reading from the Prophets is the very section Christ reads, Isaiah 61:1-2! A Jewish Quarterly Review article, "The Reading of the Law and Prophets in a Triennial Cycle," by Dr. Adolf Büchler (Vol. IV, October 1893, pp. 1-73) confirms this fact. Remember, His ministry was three-and-a-half years long. He was crucified in the spring of AD 31, so this Sabbath (possibly Pentecost) would have occurred shortly after He began His ministry.
John W. Ritenbaugh
Countdown to Pentecost 2001