The last trump is associated with and is blown on Rosh HaShanah.  The biblical name for Rosh HaShanah is Yom Teruah, which in Hebrew means "the day of the awakening blast." This trump (shofar) is mentioned by the apostle Paul (Rav Sha'ul) in First Corinthians 15:51-53. Because the last trump is only blown on Rosh HaShanah and because the apostle Paul (Rav Sha'ul) specifically mentions that the rapture (natzal) of the believers in Yeshua the Messiah will take place at the last trump, the apostle Paul (Rav Sha'ul) was giving a clear understanding that the rapture of the believers in Messiah will happen on a Rosh HaShanah.

One of the reasons for blowing the shofar is to proclaim the resurrection of the dead. In addition, the thirteenth principle of the Jewish faith is belief in the resurrection of the dead. The resurrection of the dead will take place on Rosh HaShanah (Talmud, Rosh HaShanah l6b). In First Corinthians 15:52, the apostle Paul (Rav Sha'ul) tells us that the resurrection of the dead will be "at the last trump."

Yet another name for Rosh HaShanah is Yom HaKeseh, "The Day of the Hiding" or "the Hidden Day." The term keseh or keceh is derived from the Hebrew root kacah, which means to "conceal, cover, or hide." Every day during the month of Elul, a trumpet is blown to warn the people to turn back to G-d, except for the thirtieth day of Elul, the day preceding Rosh HaShanah. On that day the trumpet is not blown, and is therefore silent. This is because much about Rosh HaShanah is concealed and shrouded in mystery. The mystical aspect of Rosh HaShanah is indicated in Scripture: "Sound the shofar on the New Moon, in concealment of the day of our festival" (Psalm [Tehillim] 81:3). Satan, the accuser, is not to be given notice about the arrival of Rosh HaShanah, the Day of Judgment. Rosh HaShanah is called Yom HaKeeh, or the Day of the Hiding, because it was hidden from satan (Ha satan), the adversary. The Bible says that satan comes to rob and to steal (John [Yochanan] 10:10, and to confu! se (1 Corinthians 14:33). Because it is the Day of Judgment, it is symbolically hidden from satan (satan did not know and understand the plan of the cross [tree], First Corinthians 2:7-8). This was hidden from him as well. Believers never said when the day of Rosh HaShanah was; they simply said, "Of that day and hour no one knows, only the Father."

One of the reasons most often given to disclaim that the resurrection of the dead and the catching away of the believers is on Rosh HaShanah is the statement given by Yeshua in Matthew (Mattityahu) 24:36, as it is written, "But of that day and hour knoweth no man, no, not the angels of heaven, but My Father only." Because Rosh HaShanah was understood to be the hidden day, this statement by Yeshua is actually an idiom for Rosh Hashanah. Thus it should be given as proof that He was speaking of Rosh HaShanah because Rosh HaShanah is the only day in the whole year that was referred to as the hidden day or the day that no man knew.

(1 Cor 15:51) Behold, I show you a mystery; We shall not all sleep, but we shall all be changed,
(1 Cor 15:52) In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
(1 Cor 15:53) For this corruptible must put on incorruption, and this mortal must put on immortality.