It is interesting that the feast of Pentecost was thought of as the festival celebrating the giving of the law. When Moses went up the Mount Sinai to receive the Ten Commandments, he went alone (Exodus 19:20). He offered to take the people up into the presence of the Lord, but they were probably afraid. When they looked up at the mountain it was on fire with lightning and smoke, making it appear a very dangerous place. Boundaries were set about the mount, so that unworthy people would not gaze upon the glory of the Lord and perish (Exodus 19:21, 23). "And the smoke thereof ascended as the smoke of a furnace" (Exodus 19:18). The Israelites did not want to become like a garment in that furnace (cf. Mosiah 12:3).
When Moses came down from Mount Sinai, however, his face shone with luster (Exodus 34:29), as did the face of Abinadi (Mosiah 13:5), as he began to recite to the priests all ten of the basic commandments of the law that Moses had received on that original day of Pentecost.
Moreover, if Abinadi’s appearances in fact occurred around the time of the feast of Pentecost, the general population would not have been in the fields, but rather gathering at the temple as the Law of Moses specifically required (Exodus 23:16–17; Deuteronomy 16:16). It was an ideal situation for Abinadi to deliver his message to a maximum number of people. His message was a strong one. He declared that "You will have burdens lashed upon your backs" (Mosiah 12:5), meaning they would become slaves, and also he said that Noah’s life would be valued as a garment in the furnace. That would have been frightening, threatening, and terrifying.
Book of Mormon Central, "Did Abinadi Prophesy During Pentecost? (Mosiah 13:5)," KnoWhy 90 (May 2, 2016).
John W. Welch, Gordon C. Thomasson, and Robert F. Smith, "Abinadi and Pentecost," in Reexploring the Book of Mormon, ed. John W. Welch (Provo and Salt Lake City, UT: FARMS and Deseret Book, 1992), 135–138.