Sequentially, we should understand the shofar at Sinai as the “first trumpet” and the “great shofar” announcing the coming of the Messiah as “the last trumpet” [1 Corinthians 15:52]. The last trumpet is the “great trumpet” of Isaiah 27:13 that signals the ingathering: “He will send forth His angels with a great trumpet” [Matthew 24:31]. At that time, “The Lord Himself will descend from heaven with a shout, with the voice of the archangel and with the trumpet of God” [1 Thessalonians 4:16]. -  D. Thomas Lancaster, Two Trumpets